REFERENCE

A Imntu SI Alts DEPARTMENT OF COMMERCE

PUBLICATION

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NBS TECHNICAL NOTE 798

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National

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Collaborative Research Program

Between NBS and

Indian Scientific Institutions

Special Foreign Currency Program

1973 Status
NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards 1 was established by an act of Congress March 3, 1901. The Bureau's overall goal is to strengthen and advance the Nation's science and technology

and facilitate their effective application for public benefit. To this end, the Bureau conducts

research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety. The Bureau consists of the Institute for Basic Standards, the Institute for Materials Research, the Institute for Applied Technology,

the Institute for Computer Sciences and Technology, and the Office for Information Programs.

THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the United

States of a complete and consistent system of physical measurement; coordinates that system

with measurement systems of other nations; and furnishes essential services leading to accurate and uniform physical measurements throughout the Nation's scientific community, industry, and commerce. The Institute consists of a Center for Radiation Research, an Office of Measurement Services and the following divisions: Applied Mathematics — Electricity — Mechanics — Heat — Optical Physics — Nuclear

Sciences " — Applied Radiation 2 — Quantum Electronics 3 — Electromagnetics 3 — Time

and Frequency 3 — Laboratory Astrophysics 3 — Cryogenics 3. THE INSTITUTE FOR MATERIALS RESEARCH conducts materials research leading to improved methods of measurement, standards, and data on the properties of well-characterized

materials needed by industry, commerce, educational institutions, and Government; provides

advisory and research services to other Government agencies; and develops, produces, and

distributes standard reference materials. The Institute consists of the Office of Standard Reference Materials and the following divisions: Analytical Chemistry — Polymers — Metallurgy — Inorganic Materials — Reactor

Radiation — Physical Chemistry.

THE INSTITUTE FOR APPLIED TECHNOLOGY provides technical services to promote

the use of available technology and to facilitate technological innovation in industry and Government; cooperates with public and private organizations leading to the development of

technological standards (including mandatory safety standards), codes and methods of test; and provides technical advice and services to Government agencies upon request. The Institute consists of a Center for Building Technology and the following divisions and offices: Engineering and Product Standards — Weights and Measures — Invention and Innovation — Product Evaluation Technology — Electronic Technology — Technical Analysis — Measurement Engineering — Structures, Materials, and Life Safety * — Building

Environment * — Technical Evaluation and Application * — Fire Technology.

THE INSTITUTE FOR COMPUTER SCIENCES AND TECHNOLOGY conducts research and provides technical sei vices designed to aid Government agencies in improving cost effec- tiveness in the conduct of their programs through the selection, acquisition, and effective

utilization of automatic data processing equipment; and serves as the principal focus within

the executive branch for the development of Federal standards for automatic data processing

equipment, techniques, and computer languages. The Center consists of the following offices and divisions: Information Processing Standards — Computer Information — Computer Services —

Systems Development — Information Processing Technology.

THE OFFICE FOR INFORMATION PROGRAMS promotes optimum dissemination and

-accessibility of scientific information generated within NBS and other agencies of the Federal Government; promotes the development of the National Standard Reference Data System and

a system of information analysis centers dealing with the broader aspects of the National Measurement System; provides appropriate services to ensure that the NBS staff has optimum

accessibility to the scientific information of the world. The Office consists of the following

organizational units: Office of Standard Reference Data — Office of Technical Information and Publications —

Library — Office of International Relations.

1 Headquarters and Laboratories at Gaithersburg, Maryland, unless otherwise noted; mailing address Washington, D.C. 20234.

3 Part of the Center for Radiation Research.

3 Located at Boulder, Colorado 80302.

* Part of the Center for Building Technology.
Nation Oi Stt»fcffe APR 2 9 1974

Collaborative Research Program Between NBS

and Indian Scientific Institutions

Special Foreign Currency Program 1973 Status

Edited by

H. Steffen Peiser, Michael B. McNeil, and

Doris M. Bluebond

Special Foreign Currency Program

Office of International Relations

National Bureau of Standards

Washington, D.C. 20234

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U.S. DEPARTMENT OF COMMERCE, Frederick B. Dent, Secretary

NATIONAL BUREAU OF STANDARDS, Richard W. Roberts, Director

Issued November 1973
National Bureau of Standards Technical Note 798

Nat. Bur. Stand. (U.S.), Tech. Note 798, 139 pages (Nov. 1973) CODEN: NBTNAE

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 (Order by SD Catalog No. C13.46:798). Price $1.50
FOREWORD

For several years the National Bureau of Standards has collaborated with technical

institutions in India through research projects conducted largely in Indian institutions,

and by occasional exchange visits of Indian and NBS scientists and engineers . This program

has been made possible through funds available under the Special Foreign Currency Program

(PL- 4 80) , in which the United States has sold agricultural commodities and other products

to India, accepting payment in rupees which remain on deposit in that country for use in

ways that are mutually agreed upon. One of these uses is to support research of interest

to both nations.

The NBS sponsored research program in India is reviewed in this publication. For

each project included in this program, the report summarizes the project goals and some

of the major results; a list of publications that resulted from the collaborative effort

is included. The names of the principal investigators in India and of the National Bureau

of Standards monitors are also included. The review should provide basic information from

which scientists and scientific administrators may form opinions on the value and efficacy

of such programs. Officials concerned with international science and technology will wish

to examine this case history of international scientific cooperation.

Our objective within NBS is to evaluate the ways in which this program has contributed

to the accomplishment of the NBS mission and to the advancement of science and technology.

Each participating Indian institution can use the report to help evaluate the ways the

program has contributed to the achievement of its own goals.

We at NBS have concluded that this program has helped us to achieve some of our

institutional goals , has contributed to the advance of science and technology , and has

established lasting technical friendships between many NBS scientists and colleagues in

India. We trust that our Indian associates share our view.

Richard W. Roberts

Director, National Bureau of Standards

111
ABSTRACT

An overview is given of grants awarded by the National Bureau of Standards under the

Special Foreign Currency Program in India, authorized by Public Law 480 and its amendments.

Each grant is identified by title, principal investigator, institution in India, NBS monitor

charged with working in close technical touch with the project in India, and the monitor's

organizational unit within NBS. The relevant work is then described briefly under the

three headings "Summary Description of Project Goals," "Results and Implications to Date,"

and "List of Publications that Resulted from the Project." To demonstrate the wide use of

such grants over the entire Program Structure of NBS , the grant descriptions are ordered by

the elements of that Program Structure. Editorial comment on the significance and purpose

of the NBS/SFCP grant program is confined to a Foreword and Introduction. The editors judge

this grant program to have had a high benefit to cost ratio from the viewpoint of NBS.

Key words: Binational research cooperation; international scientific cooperation; India

science and technology; physical science research administration; research planning;

scientific research abstracts ; Special Foreign Currency Program.

IV
TABLE OF CONTENTS

Page

INTRODUCTION 1

A.l. PHYSICAL MEASUREMENT METHODS, UNITS AND STANDARDS

S. K. Kor/M. D. Scheer, "Ultrasonic Dispersion and Absorption" 5

R. S. Krishnan and E. S. Rajagopal/P. L. M. Heydemann, "Development of High

Pressure Techniques and Some Applications" 7

A. 5. STANDARD REFERENCE DATA

M. N. Das and K. K. Kundu/R. G. Bates, J. K. Taylor, and R. A. Durst,

s "Properties of Electrolytes in Nonaqueous Media" 9

S. C. Jain/L. H. Gevantman, "Point Defects in Alkali Halides" 18

S. K. Joshi/D. Kahan, "Review of Physical Properties of Alloys" 19

A. P. Kudchadker/H. J. White, "Physical and Thermodynamic Properties of

Halogenated Alkanes" 21

C. N. R. Rao/L. H. Gevantman, "Critical Reviews of Phase Transformations in

Inorganic Solids " 24

C. N. R. Rao/L. H. Gevantman, "Infrared Bibliography" 26

C. N. R. Rao/H. S. Peiser and H. F. McMurdie, "Studies of Metal Oxides, Phase

Transitions and Related Problems" 27

G. N. Rao/L. H. Gevantman, "Magnetic Properties of Atomic Nuclei and of the

Nuclear Environment and on the Lifetimes of Nuclear States" 30

N. L. Singh/A. Bass , "Investigations of Molecular Spectra" 34

P. N. Trehan/R. S. Caswell, "The Investigation of the Decay of Even-Even

Nuclei in the Medium Weight Region'' 4-6

P. Venkateswarlu and D. Ramachandra Rao/A. Bass, "Optical Spectra of Simple

Molecules" 51

A. 6. STANDARD REFERENCE MATERIALS

V. A. Altekar and H. P. Bhattacharya/R. E.Michaelis, "Preparation of Standard

Reference Materials of Ferro-Alloys" 55

S. Kumar/0. Menis, "Glass and Ceramic Chemical Composition - SRM Program" 58

A. 8. MATERIALS MEASUREMENT METHODS AND STANDARDS

K. V. Krishna Rao/S. Block, "Low Temperature and High Pressure X-ray

Investigations of Phase Transitions" 60

C. N. Pillai and M. Satyanarayana/R. Klein, "Catalytic High Pressure

Hydrogen Transfer Reactions" 63

M. V. C. Sastri and V. Srinivasan/R. Klein, "Study of Transitrion Metal

Oxides with Special Reference to Their Catalytic Properties" 64
TABLE OF CONTENTS (cont.)

Page

B.l. MATERIALS SCIENCE AND TECHNOLOGY

V. V. Dadape/W. 3. Horizon, "Investigations in the Chemical and

Thermodynamic Properties of Refractory Materials Involving Oxides

,

Nitrides , Carbides , etc . , at High Temperatures" 70

M. M. Taqui Khan/T. D. Coyle, "Platinum Group Metal Complexes, Their

Preparation, Structure, and Role in Homogeneous Catalysis" 77

E. C. Subbarao/J. B. Wachtman, Jr., H. S. Bennett, and R. S. Roth,

"Electrical Behavior of Pure and Doped Oxides and Other Ionic Solids" 82

G. S. Verma/A. H. Kahn, "Transport Properties of Solids at Low Temperatures"., gs

B.3. BUILDING TECHNOLOGY

J. K. Sridhar Rao/E. 0. Pfrang, "Composite Structural Systems in Buildings" .. 102

V.Sundararajan and V. Kadambi/E. 0. Pfrang, "Study of Structural Elements

Under Dynamic Loading" 10 5

B . 9 . FAILURE AVOIDANCE

H. V. Gopalakrishna/F. R. Kotter, "Studies of the Electrical Breakdown

at the Junction of Metals and Solid Dielectrics in High Vacuum at High

Voltages " 107

B.ll. NUCLEAR AND RADIATION TECHNOLOGY

A. M. Ghose/R. B. Schwartz, "Experimental Investigations on the

Generalized Optical Model Parameters of Fast Neutrons" 113

A. M. Ghose/E. G. Fuller and J. H. Hubbell, "Investigations on the

Interaction of Gamma Rays with Matter" 116

P. P. Kane/J. W. Motz , "Gamma Ray Scattering, I" . 120

P. P. Kane/ J. H. Hubbell, "Gamma Ray Scattering , II" 122

APPENDIX I - SFCP (PL 480) BACKGROUND HISTORY 123

APPENDIX II - NBS PROGRAM STRUCTURE 125

APPENDIX III - LIST OF SFCP GRANTS IN INDIA 127

APPENDIX IV - ALPHABETIC LIST OF NBS MONITORS 130

APPENDIX V - ALPHABETIC LIST OF PRINCIPAL INVESTIGATORS 131

APPENDIX VI - INDEX OF INSTITUTES 132

vi
COLLABORATIVE RESEARCH PROGRAM BETWEEN NBS AND INDIAN SCIENTIFIC INSTITUTIONS

Special Foreign Currency Program 1973 Status

Edited by

H.Steffen Peiser, Michael B. McNeil, and Doris Bluebond

1. INTRODUCTION

Information on scientific research and technical innovation is normally published in

specialized journals and a literature devoted to abstracts of such reports enables a

specialist to find material related to his own interests. The present publication, a collection of summaries of scientific research, has a purpose different from those associated with

such conventional publications . We , the editors , have assembled evidence on which a cooperative scientific program can be evaluated; we are not trying to inform scientists in

specialized fields about recent scientific news. We are viewing the overall Special Foreign

Currency Program of the National Bureau of Standards in India over roughly the past five

years. We are here presenting not our own assessment of the program but are, rather,

attempting to present sufficient information in a useful form for the program to be evaluated by interested persons. In this connection, requests for more detailed additional

information would always be welcome as would comments and criticisms of the program. We are

ourselves aware that certain features of the program could be improved in the future.

Special assessment of this program is needed because it is an unusual one. Such an

assessment could well be done from a number of viewpoints ; for instance , those of the

grantor and grantee institutions as well as from those relating to the broad national

goals of each country. The program has already been carefully examined from the point of

view of the NBS by NBS management and found to be of assistance in carrying out its mission.

The program supplements the research output of the NBS and enhances international collaboration involving its scientists. The program may have other significance: it demonstrates

a technique by which a smaller less wealthy country can keep in touch with a larger country

when both are highly developed scientifically; and, in some instances, it may offer the

opportunity to develop a specialized competence in one of the two countries where previously

such competence did not exist.

Staff members of NBS have reacted favorably to this program. A number of NBS personnel

have commented that their own individual SFCP projects have been successful and relevant,

and they have very strongly encouraged us to present them with sufficient information to
allow them to take a broader view of the program so as to enable them to see it in its

entirety. This Technical Note is an attempt at presenting the requisite information,

relating to grants at Indian institutions, for producing such an overview. This Technical

Note follows similar publications relating to such NBS grants in Israel and Yugoslavia.

A person attempting an analysis and evaluation of this Program need not necessarily

concern himself with administrative details. For those who are interested, the editors

have included some background administrative and historical material in Appendix I. To

carry out its responsibilities under the various Acts of Congress, by which U.S. federal

agencies have had the opportunity to use certain excess foreign currencies in India for

the pursuit of scientific research and technical development work, the National Bureau of

Standards has adopted guidelines for its Program, as also reprinted in Appendix I.

The reader examining the program from the grantor country's point of view has the

opportunity to judge whether it has increased the research output of NBS appreciably and,

if so, whether this has been in useful directions; and also, whether U.S. national goals

were served. To make this task easier we have assembled the sections of this Technical

Note into categories identified by the NBS Program Structure under which all NBS projects

are classified. The list of these Program Structures appears in Appendix II.

The reader oriented to the Indian viewpoint, on the other hand, should ask whether new

techniques really have been brought to India by these projects and whether techniques

already in existence have been given the opportunity to develop. Questions should be

raised , such as : Have new competences been built up and old ones strengthened or have

scientific and technological talents been diverted from the real national goals of India

towards the longer-range goals of the USA? Have neighboring fields been enriched in India

by cross-fertilization, have applications in industry been sparked, and has the program

helped to provide India with a broadly based infrastructure of science and technology?

Have graduate students assigned to the projects received training which ultimately will

benefit India?

Readers with more specific viewpoints will ask such questions as

:

1. Were the projects in the fields familiar to you well executed?

2. Did the senior investigators demonstrate exceptional competence which could be

of special service in the future?
3. Did the projects contribute to problems of known importance to science,

technology, or society?

4. Is there evidence that contact between U.S. and Indian scientists was

intellectually stimulating and helpful perhaps in related work?

5. Does the program appear to have contributed to forming a good climate for

scientific progress and technological innovation?

6. Did the program help to widen the horizons of scientists towards application

of their expertise to urgent national needs?

7. Does this report suggest that bi-national programs of this type should be

developed for mutual benefit?

This list of questions is certainly not exhaustive nor are their answers by any means

obvious

.

This Technical Note is addressed most particularly to scientifically trained science

administrators. In it the editors have summarized approximately $950,000 worth of funded

research. In many instances the projects were considered valuable enough by Indian

officials for them to have often augmented NBS support from other sources . Salary costs

of faculty members were provided by the Indian institutions.

The NBS monitor has been strongly encouraged to carry on direct communication with the

principal investigator. Visits by NBS monitors to India have broadened the basis of interaction. Whenever it has become necessary, for scientific reasons, for an NBS monitor to

visit his project in India, he has been strongly urged to visit as many additional

scientific institutions and laboratories as possible and to describe, in writing, on his

return, his view of the scientific competences and the particular strengths and weaknesses

which he observed. In addition to serving to broaden the outlook of the NBS monitor, the

visits increase the contacts between Indian scientists and the NBS staff, thereby enabling

the Indian scientists to understand NBS better. This increases the likelihood that Indian

scientists involved in the program will, to a certain extent, insert into their projects

an NBS point of view in addition to their own. By careful planning of such NBS staff visits

their cost has been restrained to less than 2 percent of project funds available, despite

the costly airfare.
Visits by Indian principal investigators to NBS are rare events because the Government

of India requires special justification to give such travel the high priority needed to use scarce foreign currency reserves. NBS collaborators would have preferred to see more

Indian colleagues in their laboratories at NBS, but they realize that the Indian

authorities necessarily view this program in a context of many competing urgent needs for

foreign currency.

Whereas the effective output from several projects might have been enhanced by such

visits , the actual accomplishments are nevertheless significant as is clearly shown in the

succeeding pages of this Technical Note. For example; new spectroscopic data have been

recorded, collections of critically evaluated data on physical properties have been made

available, standard reference materials have been developed, nuclear cross- sections and

angular correlations have been studied, analytical procedures for estimating trace elements

in glasses have been elucidated, catalytic activities have been related to the structures

of oxides , high temperature transformations in oxides have been examined , new metalloorganic compounds have been prepared , methods for the suppression of electrical breakdown

at high voltages have been scrutinized, and types of building structures have been

observed under dynamic and static loads.
A.I.* PHYSICAL MEASUREMENT METHODS, UNITS AND STANDARDS

Project Title : ULTRASONIC DISPERSION AND ABSORPTION

Principal Investigator : Dr. S. K. Kor

Institution : Allahabad University, Allahabad

NBS Monitor : Dr. M. D. Scheer

NBS Institute or Center and Division : Institute for Materials Research

Physical Chemistry Division

Summary Description of Project Goals

Ultrasonic dispersion and absorption will be studied in pure liquids, electrolytic

solutions , and liquid crystals in order to determine the relaxation kinetics for processes

which are characteristic of these systems. For example, molecular and ion-association

rates can be determined in polar liquids and electrolytic solutions by this method. The

study of liquid crystals by this technique is a new area of investigation and may lead to

important new insights into the behavior of these interesting substances. The color

changes in liquid crystals are very temperature sensitive and can be used for the detection

of microwave heating , of chemical vapors , and of ultraviolet and infrared radiation

.

Results and Implications to Date

Ultrasonic absorption and velocity measurements have been made in the following alkali

halides : NaCl , NaBr , Nal , KC1 , KBr , KI , RbCl , Rbl , Csl , LiF , and LiCl in mixed solvents

using a pulse technique at 25 C. The total absorption in the solvent can be written as:

(a/f 2 V . . = (a/f2

) . .. + (a/f 2

) . . , total shear viscosity structural

as the contributions due to thermal conduction and thermal relaxation are negligible.

Since the alkali halides show practically no association, absorption in solution is assumed

to be controlled by the above two factors. The contribution due to shear viscosity is

obtained from the relation:

(a/f ) . . = —5— —

r

shear viscosity 3 pc°

Using the above two relations, a structural contribution can be obtained. For the same

halide ion, the shear viscosity is found to decrease in the order Li, Na, K, Rb whereas

for the same cation the decrease is in the order CI, Br, I.

* The alphanumeric designation refers to the NBS Program Structure (see Appendix II)
Ultrasonic absorption and velocity measurements have been made in eugenol in the temperature range - 50 C at 45 MHz. The various contributions to the total ultrasonic

absorption are:

(a/f2

) +

. , = (a/f2

) , + (a/f2) + (a/f2 )^ , total shear comp. thermal

2tt 2 4 + + (a/f

2

) pc^ 3s c thermal

where n and n are the shear and compressional viscosities respectively. Work is in

progress on the various contributions of ultrasonic absorption in eugenol.

Future plans consist of work in the following directions

:

(i) Ultrasonic absorption and velocity measurements in pure

liquids and interpretation of the results.

(ii) Ultrasonic absorption and velocity measurements in liquid crystals.

Arrangements for making measurements in the high temperature region

are in progress.

(iii) Ultrasonic absorption and velocity measurements in electrolytic solutions

and the study of ion-association. Ion-association is presently not clearly

understood. Yet it is a phenomenon which influences many chemical processes.

List of Publications that Resulted from the Project

This project was funded only recently so that there are no publications as yet.
A.I.* PHYSICAL MEASUREMENT METHODS, UNITS, AND STANDARDS

Project Title : DEVELOPMENT OF HIGH PRESSURE TECHNIQUES AND SOME APPLICATIONS

Principal Investigators : Professor R. S. Krishnan

Professor E. S. RajagoDal

Institution : Indian Institute of Science, Bangalore

NBS Monitor : Dr. P. L. M. Heydemann

NBS Institute or Center and Division : Institute for Basic Standards

Heat Division

Summary Description of Project Goals

The main objective of the project is to develop instrumentation for the generation

of high pressures, in stages, up to 100 kbar, and to use the equipment to measure physical

properties such as optical and dielectric properties , critical phenomena and phase transitions. Studies of resistivity and nuclear quadrupole resonance (NQR) will also be attempted. All these measurements are now carried out in the laboratory at 1 atm. conditions.

Results and Implications to Date

Work on the project started in October, 1972. An arrangement is being set up to study

the optical behavior of materials up to about 7 kbar. The substance to be studied is contained between a pair of Bridgman opposed anvils , and is pressurized by a standard hydraulic press . The optical path is parallel to the pressure axis , thereby reducing the effect

in the studies of pressure gradients across the anvil face. Sapphire anvils, to be used

in the final measurements, are being ground. Tungsten carbide anvils for use up to 40 kbar

are being procured. Preliminary trials upto 1 kbar have been performed using simple glass

anvils. A tubular furnace surrounding the anvil assembly is used to vary the temperatures.

The preliminary design and the drawings for a piston-cylinder apparatus are being

made.

Calculations on the stability of the diamond structure at high pressures has been

completed. The bond bending and bond stretching force constants at high pressures have

been estimated for diamond, Si, Ge, CaAs and GaSb. It is found that their ratio has a

critical value ^ 0.04 to 0.08 when the structural change occurs.

* The alphanumeric designation refers to the NBS Program Structure (see Appendix II).
The NBS monitor states that the work performed in the High Pressure Group of the

NBS Pressure and Vacuum Section and at the Indian Institute of Science is directed toward

the establishment of a high pressure scale. In the past considerable effort was spent on

the investigation of phase transitions and other properties of materials that could be

used as fixed points on the pressure scale. Now most of this activity will be moved to

IIS and concentration will be instead on the development of a transfer gage for high

pressures. This transfer gage will then be used both at NBS and at IIS to tie the fixed

points to the scale.

NBS is particularly interested in the IISc work on NQR. Several years ago NBS began

to study the possibility of using NQR as an extremely stable transfer device. Lack of manpower forced abandonment of the project at NBS, but it is now being revived under this

grant.

List of Publications that Resulted from the Project

1. S. N. Vaidya, "Stability of Diamond and Zinc Blende Structures at High Presssures,"

Current Science (accepted for publication)

.
A. 5." STANDARD REFERENCE DATA

Project Title : PROPERTIES OF ELECTROLYTES IN NONAQUEOUS MEDIA

Principal Investigators : Dr. Mihir Nath Das

Dr. Kiron Kumar Kundu

Institution : Jadavpur University, Calcutta

NBS Monitors : Dr. Roger G. Bates (up to September 1969)

Dr. John K. Taylor (1969-70)

Dr. Richard A. Durst (1970)

NBS Institute or Center and Division : Institute for Materials Research

Analytical Chemistry Division

Summary Description of Project Goals

The main object of the project was to collect standard physico-chemical data for

solutions of electrolytes in nonaqueous solvents and their aqueous mixtures , and as an

essential prerequisite to such studies , to develop suitable methods for accurate

measurements of the desired quantities. The investigations under the project have yielded

useful physico-chemical data which should be of value for an understanding of the properties of electrolyte solutions in general, and are also likely to prove useful in relation

to some electrochemical processes of technological importance.

Results and Implications to Date

The experimental work mainly involves the determination of the standard potentials

of the silver-silver halide (chloride, bromide, and iodide) electrodes and M/M electrodes

(M = Li, Na, K, and Cs) in ethylene glycol (EG) and its aqueous mixtures as well as in

propylene glycol (PG) and its methanolic mixtures. The thermodynamic dissociation constants of several acids of different charge types have also been determined by potentiometric or spectrophotometric measurements . The related thermodynamic quantities have

been evaluated from the data obtained.

A. Standard electrode potentials in ethylene glycol (EG) - water solvent system

and related thermodynamic quantities.

(i) The standard potentials (E ) of the Ag-AgCl electrode in EG and its

aqueous mixtures of varying compositions have been determined at

different temperatures (5-45°C) using a cell of the type A [1] .

" The alphanumeric designation refers to the NBS Program Structure (see Appendix II)

1 Figures in square brackets indicate the publication reference at the end of this

project review.
Pt/H (g, 1 atm)/HCl(m), solvent/AgCl-Ag ... type (A)

For the Ag-AgI electrode [4, 13] and the Ag-AgBr electrode (in Dure EG) [2]

the cell of the type A was found unsuitable , and a cell of the type B was

used.

Pt/H (g, 1 atm)/HOAc(m ), NaOAcCm ) , NaXCmJ , solvent/AgX-Ag ... type

(B) , where X = Br or I and HOAc denotes acetic acid, whose dissociation

constants in the different solvent media were first determined using the

Ag-AgCl electrode in the cell of the type B, E of the Ag-AgCl electrode

being known from previous independent measurements with cells of the type A.

The E values (molal scale) so obtained at different temperatures have been

fitted in the form of Harned-Robinson type equations , using the least

squares method:

E° = A - B (t - 25) - C (t - 25)

2 ... (1), m

where t denotes the temperature on the Celsius scale.

The standard potentials on the mole fraction scale (E,.) were calculated

from E , and the standard free energy of transfer (AG ) at 25 C of one mole

of HX from water to another medium was evaluated from E„, by using the

reported value of E for water. From the temperature coefficients of the

standard potentials, the standard entropy of transfer (AS ) and hence the

standard enthalpy of transfer (AH ) at 25 C were also computed, using

equation (1) [13]. For HBr, the relevant E date previously determined in

this laboratory have been used.

(ii) The standard potentials of M/M electrodes (M = Li, Na, K, and Cs) [6,12] in

Eg and its aqueous mixtures of varying composition have been determined at

25 C, using a cell of the type C in conjunction with a cell of type D, the

concentration of the alkali metal in the amalgam being the same in C and D. M (Hg)/MBr(m), solvent/AgBr-Ag ... type (C)

M (Hg)/MBr(m), water/AgBr-Ag ... type (D)

The activities of the amalgams used were evaluated from the emf 's of the

cell D by using the reported activity of MBr at the respective values of m

10
(m = 0.10, 0.20, and 0.50) in aqueous solutions, and the standard

potentials of M/M and Ag-AgBr electrodes in water. These values were

used to compute the standard emf's ( E , , ) of the cell E.

M/MX, solvent/AgX-Ag ... type (E)

,

where X = Br.

By coupling the standard potentials of M/M electrodes with those of

the Ag-AgCl and Ag-AgI electrodes determined earlier, the values of

( E , ,) were obtained for X = CI and I, for the different media. The

s ceJ L -p values of ( E -, , ) on the mole fraction scale were utilized to evaluate

s cell -£ the standard free energies of transfer, AG (MX) , of MX electrolytes from

water to glycol and its aqueous mixture [12].

Thermodynamic dissociation constants of some acids of different charge types in

ethylene glycol (EG) - water solvent system.

A cell of the tyoe F has been used to determine the acidic dissociation

constants of ammonium and several alkylammonium ions in pure EG at nine

temperatures (5-45°C) [3].

Pt/H (g, 1 a-bn)/BH

+Br~(m

1

), B(m ) , solvent/AgBr-Ag ... type (F)

where B is an amine base.

The pKDtJ+ values at different temperatures have been fitted into HarnedRobinson type equations by the method of least squares.

pK

BH

+ = a/T + b + cT ... (2)

The standard thermodynamic quantities , AG , AH , AS , and AC for the

dissociation of the acids in EG have been computed from the constants of

equation ( 2 )

.

The dissociation constants of protonated tris(hydroxymethyl)aminomethane

( tris . H ) , and monoethanolamine have been determined at different temperatures

using a cell of type F, in a series of aqueous mixtures of EG. The constants

a, b, and c of equation (2) have been calculated.

The dissociation constants (K ) of protonated m- and p- mitroanilines (BH )

and thymolsulphonphthalein (H_A and HA ) have been determined at 25 C in aqueous

mixtures of EG by spectrophotometric measurements [14].

11
C. Standard electrode potentials in "isodielectric" media comprising propylene

glycol (PG) and methanol.

(i) The standard potentials of the Ag-AgCl electrode in PG [2] and its

methanolic mixtures [8,15] (which serve as nearly isodielectric media)

have been determined at different temperatures using a cell of the type

A. The E values of the Ag-AgCl electrode at different temperatures

have been fitted in equation (1). The standard free energies (AG,),

enthalpies (AH ), and entropies (AS ) of transfer of one mole of HC1 from

methanol to PG and its methanolic mixtures have been calculated.

The standard potentials of the Ag-AgBr electrode in PG-methanol

mixtures [8] have been determined at 25 C, using a cell of the type B,

the required K values of acetic acid in the different media having been

obtained as in Section A Cii)

.

(ii) The standard potentials of M/M (M = Li, Na, K) electrodes in PG-methanol

solvent system [10] have been determined at 25 C by using cells of the

types C and D. These values have been utilized, as in Section A(ii) , for

computing the standard emf's ( L° -.,)„ of the cell E (for X = CI and Br)

and hence the standard free energy changes AG (MX) accompanying the transfer

of MX from methanol to the other media.

D. Thermodynamic dissociation constants of some acids in "iso-dielectric" media

comprising methanol and propylene glycol (PG).

The dissociation constants of benzoic acid, protonated tris(hydroxymethyl)-

+ o aminomethane and p-nitroanilinium ion (p.n.a.H ) have been determined at 25 C m

methanol-PG solvent system by emf measurements of suitable galvanic cells in the

first two cases, and by spectrophotometric measurements for p.n.a.H [11].

E. Miscellaneous measurements relating to proton transfer equilibria in glycolic

media

.

(i) Autoprotolysis constants:

The autoprotolysis constants (K ) of ethylene glycol (EG) and

propylene glycol (PG) have been evaluated at different temperatures.

The pK values can be expressed in the form of equation (2) as a function

of temperature on the Kelvin scale [5]. 12
The autoprotolysis constants of methanolic mixtures of PG [9] have been

determined at 25 C.

(ii) Acidity Functions (H_) in ethylene glycol (EG):

Acidity function (H_) scales have been set up for glycoxide solutions

of lithium (0.10 - 1.0 M) and sodium (0.10 - 3.0 M) in EG at 25°C by the

use of several nitrosubstituted aniline and diphenylamine indicators [7].

The pK values of the indicator acids used referred to EG are as follows

(1) 2,4,4'-trinitrodiphenylamine = Cm. 35); (2) 2 , 4 , 3 ' -trinitrodiphenylamine = (14.95); (3) 6-bromo-2,4'-dinitroaniline = (16.185); (4) 2,4-dinitrodiphenylamine = (16.445).

F. Solvent effects on the electrolytes and protonation equilibria in glycolic media.

Attempts have been made to analyze the thermodynamic quantities obtained

from the above studies in the light of solute-solvent and solvent-solvent interactions .

The values of AG°(HX) at 25°C for the transfer from water to EG and its

aqueous mixtures have been split up into the components for the individual ions

,

AG (i), by a method of extrapolation essentially based on the Born equation.

By using the values of AG, (X) so obtained, the values of AG, (i) for the alkali

metal ions CM ) at 25 C have been evaluated. For a better understanding of the

solute-solvent interactions involved,' the "chemical" contributions, AG, -, Ci), t,ch

for M and X~ ions were evaluated by subtracting from AG Ci) the electrostatic

contributions obtained on the basis of the Born equation by using the respective

crystallographic radii of the ions. The results indicate that cations are

glycophilic and the anions hydrobhilic [13].

The values of AS (i) as well as AS ,(i) , and hence of AH (i) and AH ,(i) ,

were also obtained in a similar manner. The results tend to suggest that unlike

monohydric alcohols , glycol in the initial stages of addition to water does not

promote enhanced structure in water, but on further addition, glycol causes breakdown of water structure like other alcohols [13].

The AG° values of the MX electrolytes for the transfer from methanol to PG

and its methanolic mixtures have likewise been split up into AG Ci) for M and X~,

13
and hence AG (H ) has also been evaluated. The media comprising methanol and

PG being very nearly isodielectric , the electrostatic contributions to AG. (i) are

expected to be negligibly small, and hence the AG (i) values directly reflect

the "chemical" effects of the solvents on the transfer process. The results

indicate that the cations are methanophilic whereas the anions are glycophilic

[10].

The values of AS°(HC1) and AH°(HC1) suggest that when PG is added to

methanol, or vice versa, in either extreme region there occurs a breakdown

of the individual solvent structures , releasing monomeric forms of the solvent

dipoles. In the intermediate region, however, the data suggest the formation

of some sort of hydrogen-bonded clusters among the solvent dipoles [15].

The thermodynamic quantities accompanying the dissociation of the

different substituted ammonium ions in ethylene glycol indicate that, besides

the inductive effect , the solvophilicity of the substituents towards glycol

plays a dominant role in the overall Drocess [3].

The thermodynamic quantities accamDanying the self-ionization of EG and PG

and the chemical contributions to these quantities as evaluated on the basis of

the Born equation indicate the absence of any water-like characteristic structure

in these solvents in spite of possible larger association due to hydrogen

bonding [5]. The autoprotolysis constants of PG-methanol mixtures at 25 C

suggest that the acidity of the mixed solvent increases and the basicity decreases as the proportion of PG is increased [9].

The understanding of the solvent effect on the proton transfer equilibria

involving a conjugate acid-base pair A and B becomes relatively easier when

one considers the free energy change, AG [A — BJ , accompanying the transfer

process (3) from a reference solvent S to any other solvent S.

S H

+

(s ) + S(s) + A(s) + B(s ) = S (s ) + SH

+ (s) + A(s ) + B(s) ... (3) o o o o o o

where (s) and (s ) indicate the substances in their standard states in the

o solvent S and the reference solvent S respectively. Thus

14
AG° [A - BJ = 2.303 RT

t 1— —J sys

p ( K ) - p( K ) S a A

So a A

= AG°(H

+

) + AG°(B) - AG°(A) ... (4),

where AG (H ) stands for the free energy change accompanying the process (5),

i.e. the transfer of H from the standard state in the reference solvent So

to the standard state in the solvent S.

S H

+

(s ) + S(s) *• SH

+ (s) + S (s ) ... (5) o o o o

The solvent effects on the dissociation of protonated tris and metaand para- nitroanilines (A = BH ) in EG-water mixtures [14] at 25 C have

been interpreted in terms of the standard free energies of transfer (AG ) , from

water to the aqueous glycol solvents , of the uncharged bases (B) , evaluated

from the measured solubilities, of the hydrochlorides of the bases (B, HC1)

,

computed from the corresponding values for HC1 and also the individual ions

assessed from the previous values of AG (Cl~).

Similarly the solvent effects on the dissociation of protonated tris

and para-nitroaniline (A = BH ) and of benzoic acid (A = HA and B = A~) in

PG-methanol solvent system at 25 C have also been interpreted [11].

The overall behavior of the different protonated amines with different

chemical nature and also with different solvophilism is found to be largely

dictated by the specific solute-solvent interactions , besides the effect of

the relative solvent "basicities" as reflected in the values of AG, (H ) for

the different media. It also appears that the protonic character of the

hydroxylic hydrogen atom is weaker in ethylene glycol than in water, whereas

the negative charge density on the oxygen atom is larger in glycol. Thus

water is more "acidic" and less "basic" than ethylene glycol. Methanol, on

the other hand, appears to be less "acidic" and more "basic" than propylene

glycol

.

15
List of Publications that Resulted from the Project

1. Utpal Sen, K. K. Kundu, and M. N. Das, "Standard Potentials of Ag-AgCl Electrode in

Ethylene Glycol and its Aqueous Mixtures at Different Temperatures and Related Thermodynamic Quantities," J. Phys. Chem. , 71 3665 (1967).

2. K. K. Kundu, P. K. Chattopadhyay , Debabrata Jana, and M. N. Das, "Standard Potentials

of Ag-AgX (X = CI or Br) Electrodes in Glycol Solvents at Different Temperatures and

Related Thermodynamic Quantities," J. Chem. Eng. Data, 15, 209 (1970).

3. K. K. Kundu, P. K. Chattopadhyay, and M. N. Das, "Thermodynamics of Proton Transfer

Processes Involving Ammonium and Substituted Ammonium Ions in Ethylene Glycol," J. Chem.

Soc. (A), 2034 (1970).

4. K. K. Kundu, Debabrata Jana, and M. N. Das, "Standard Potentials of Ag-AgBr Electrode

in Propylene Glycol and of Ag-AgI Electrode in Ethylene and Propylene Glycols at

Different Temperatures and Related Thermodynamic Quantities," J. Phys. Chem. ,74_, 2625

(1970).

5. K. K. Kundu, P. K. Chattopadhyay, Debabrata Jana, and M. N. Das, "Thermodynamics of

Self-Ionization of Ethylene and Propylene Glycols," J. Phys. Chem., 74, 2633 (1970).

6. K. K. Kundu and A. K. Rakshit, "Standard Potentials of Cs/Cs

+ Electrode in Ethylene

Glycol and 50% Glycol-Water Mixtures and Test of Strehlcw's Method for Standard Free

Energy of Transfer for Individual Ions from Water to these Solvents," Indian J. Chem.

,

Si, 439 (1971).

7. K. K. Kundu and Lakshmi Aiyar, "Acidity Functions (H_) of Lithium, Sodium and Potassium

Glycoxide Solutions in Ethylene Glycol," J. Chem. Soc. (A), 40 (1971).

8. K. K. Kundu, A. L. De, and M. N. Das, "Studies in Iso-dielectric Media, Part I,

Standard Potentials of Ag-AgX (X = CI or Br) Electrodes in Methanol-Propylene Glycol

Media," J. Chem. Soc (Dalton) , 373 (1972).

9. K. K. Kundu, A. L. De, and M. N. Das, Ibid. Part II, "Autcprotolysis Constants of

Methanol-Propylene Glycol Mixtures at 25°C," J. Chem. Soc. (Dalton), 378 (1972).

10. K. K. Kundu, A. K. Rakshit, and M. N. Das, Ibid. Part III, "Standard Potentials of M/M

+

(M = Li, Na, K) Electrodes in Methanol-Propylene Glycol Solvent System," J. Chem. Soc.

(Dalton), 381 (1972).

16
11. K. K. Kundu, A. L. De, and M. N. Das, Ibid. Part IV, "Solvent Effect on Proton Transfer

Equilibria of Some Acids in Methanol-Propylene Glycol Solvent System at 25 C, 1, J. Chem.

Soc. (Dalton), 386 (1972).

12. K. K. Kundu, A. K. Rakshit, and M. M. Das, "Standard Potentials of Li/Li

+

, Ma/Na

+ and

K/K Electrodes in Ethylene Glycol and its Aqueous Mixtures at 25 C and Related

Thermodynamic Behaviour of the Alkali Halides," Electrochim. Acta, 17, 1921 (1972).

13. K. K. Kundu, Debabrata Jane, and M. N. Das, "Standard Potentials of Silver/Silver

Iodide Electrode in Aqueous Mixtures of Ethylene Glycol at Different Temperatures and

Thermodynamics of Transfer of Hydrogen Halides from Water to Glycolic Media,"

Electrochim. Acta (in press).

14. K. K. Kundu, A. L. De, and M. N. Das, "Solvent Effects on the Dissociation of

Protonated Tris (Hydroxymethyl) aminomethane and p-Nitroanilinium Ion in WaterEthylene Glycol Media at 25°C," J. Chem. Soc. (Perkin II), (in press).

15. K. K. Kundu, Debabrata Jana, and M. N. Das, "Studies in Some Isodielectric Media

Part V, Standard Potentials of the Ag-AgCl Electrode in Methanol-Propylene Glycol

Solvent System at Different Temperatures and Related Thermodynamic Quantities,"

Electrochim. Acta (accepted)

.

17
A. 5.- STANDARD REFERENCE DATA

Project Title : POINT DEFECTS IN ALKALI HALIDES

Principal Investigator : Professor S. C. Jain

Institution : Indian Institute of Technology , Delhi

NBS Monitor : Dr. Lewis H. Gevantman

NBS Institute or Center and Division: Office of Associate Director for Information

Programs ; Office of Standard Reference Data

Summary Description of Project Goals

The purpose of this project is to collect, evaluate and compile critical tables of

standard reference data on defect properties of non-metallic crystals

.

Results and Implications to Date

The project started in 1968 with the aim of collecting and compiling a bibliography

and also tabulating the critical tables of standard reference data on defects in alkali

halides. The international journal literature is surveyed to collect the data. In addition, Physics Abstracts, Solid State Abstracts and Current Papers in Physics are reviewed

to check on the thoroughness with which the pertinent literature is covered. A bibliography containing —3000 references was published in 1971. By the end of 1971 the

collection of the data on properties of defect centers in alkali halides was completed.

The data have now been critically evaluated and the most reliable values compiled in the

form of tables on "Electronic Absorption and Internal and External Vibrational Data of

Atomic and Molecular Ions Doped in Alkali Halides . " It is hoDed that the tables will be

published soon.

List of Publications that Resulted from the Project

1. S. C. Jain, S. A. Khan, H. K. Sehgal, V. K. Garg, and R. K. Jain, "Bibliography on

Properties of Defect Centers in Alkali Halides," Report No. NBS-0SRDB-71-1, National

Technical Information Service, Springfield, Virginia (Jan. 1971).

- The alphanumeric designation refers to the NBS Program Structure ( see Appendix II )

.

18
A. 5." STANDARD REFERENCE DATA

Project Title : REVIEW OF PHYSICAL PROPERTIES OF ALLOYS

Principal Investigator : Professor S. K. Joshi

Institution : University of Roorkee, Roorkee

NBS Monitor : Mr. Daniel Kahan

NBS Institute or Center and Division : Institute for Materials Research

Metallurgy Division

Summary Description of Project Goals

The aim of this project is to collect and critically evaluate experimental data for

various alloys with particular emphasis on disordered phases. Theoretical interpretations

of the evaluated data will be attempted. This work is to be done in support of and in

close collaboration with NBS which is presently engaged in its Alloy Data Center in collecting, indexing and evaluating the large amount of published data on physical properties of

alloys. This is a very large task for which assistance from expert groups in other

countries is welcomed. India with a rapidly increasing technological and industrial involvement in complex alloys needs an awareness and detailed knowledge of the existence and

availability of complex new materials and their behavior for specific applications and

possible manufacture. This collaboration therefore can be of benefit to both

parties involved and ultimately to world technology.

Results and Implications to Date

The project started in October 1972 with the object of compiling and critically

assessing experimental data which are of major importance in the study of alloys. The

principal investigator of the project has been entrusted with the task of reviewing the

properties of alloys on the topics listed below:

1. Calculation of the electronic density of states.

2. Optical constants.

3. Specific heat.

4. Electrical conductivity.

5. Phonon frequencies.

6. Positron annihilation and Kohn effect measurements for Fermi surfaces.

• c The alphanumeric designation refers to the NBS Program Structure ( see Appendix II )

.

19
7. Order-disorder studies from x-ray and neutron diffraction.

8. Phase diagrams.

9

.

Superconductivity

.

The NBS Alloy Data Center is already engaged in reviewing and evaluating the literature on Knight shift and soft x-ray spectroscopies. Nevertheless, these two areas will

receive marginal attention in this project.

The investigator of the project has undertaken the responsibility of submitting

periodically bibliographic compilations to the Alloy Data Center. Some of the material

has already been dispatched and found to be suitable for incorporation in the base

information available at that Center. It has also been possible to review the scheme

of annotations used by the Data Center and suggest some modifications which have been

approved as significant improvements

.

List of Publications that Resulted from the Project

This project was started only recently and no publication has as yet resulted.

20
A. 5.- STANDARD REFERENCE DATA

Project Title : PHYSICAL AND THERMODYNAMIC PROPERTIES OF HALOGENATED ALKANES

Principal Investigator : Dr. Arvind P. Kudchadker

Institution : Kanpur Critical Data Center, Indian Institute of Technology, Kanpur

NBS Monitor : Dr. Howard J. White, Jr.

NBS Institute or Center and Division : Office of Associate Director for Information

Programs , Office of Standard Reference Data

Summary Description of Project Goals

The project involves an exhaustive literature survey, compilation, evaluation,

selection , and correlation of physical and thermodynamic properties of bromo- , iodo-

,

and mixed fluorochlorobromoiodo alkanes. Refractive index, density, vapor pressure-boiling

points , transition and freezing points , and critical constants are the physical properties

investigated. The thermodynamic properties are also computed from the spectroscopic information. It is expected that this study will result in complete and detailed reports on

most of the following : ( 1 ) bromo- , iodo- and mixed methanes ; ( 2 ) Bromo- , Iodo- and mixed

ethanes ; ( 3 ) tromo- , iodo- and mixed higher alkanes ; and ( 4 ) development of correlation

techniques for the prediction of properties for which compounds , data are not available

.

It is expected that some of the products of this Center will be sets of critically

evaluated data which will contribute to the overall coverage of the thermodynamic and

physical properties of organic compounds for the National Standard Reference Data System.

In this task the Center will cooperate closely with the Thermodynamics Research Center at

Texas A and M University which has similar tasks and with the Office of Standard Reference

Data. Many classes of organic compounds are of great importance because of their widespread use in industry.

Results and Implications to Date

The project started in August 1970 with the purpose of collecting and compiling data

from 1908 onwards through a detailed, systematic, and exhaustive literature survey on

bromoiodo methanes. For each property, the collected data were arranged in chronological

order for each compound and the compounds were arranged in standard order.

In this fashion summary sheets were prepared for the above mentioned properties.

Then followed systematic and critical evaluation, and selection of "best" data for each

" The alphanumeric designation refers to the NBS Program Structure (see Appendix II)

.

21
property and for each compound. Both graphical and computational techniques were used f<

this purpose. Various existing models were selected to fit the data for ease of interpolation and limited extrapolation. Out of a total of 69 halogenated methanes , reliable data on

physical properties are available for about 15 compounds . The spectroscopic information is

available for about 40 compounds. The available data on halomethanes have been arranged in

tabular form to show the existence and the lack of data on properties for the compounds

studied. This table is useful for the recommendation of needed future experimental work.

Simultaneously, the literature survey was continued on haloethanes. The work completed by

August 1972 is the following:

1. Literature survey, data compilation in the form of summary sheets, evaluation,

selection, and correlation of the above mentioned properties for fluoro-, chloro-,

bromo- , iodo- , substituted methanes

.

2. Literature survey,. data compilation in the form of summary sheets, and evaluation

and selection on haloethanes.

3. Literature survey on vapor-pressure-boiling points, enthalpy of vaporization,

virial coefficients , intermolecular forces , and P-V-T data for selected organic

substances

.

In addition to the publications mentioned in the subsequent section, the following

manuscripts are in preparation:

1. S. A. Kudchadker and A, P. Kudchadker, "A Generalized Bond and Interaction Scheme

for Thermodynamic Properties of Haloethanes .

2. V. K. Goyal and A. P. Kudchadker, "Vapor Pressure-Boiling Point Relationships -

A New Vapor Pressure Equation.

3. P. R. Patnaik, P. P. Misra, Shukla, and A. P. Kudchadker, "Densities, Vapor

Pressures, and Enthalpy of Vaporization of Halomethanes."

4. S. A. Kudchadker and A. P. Kudchadker, "Ideal Gas Thermodynamic Properties of

Bromo- and Iodomethanes .

5. A. P. Kudchadker, "Virial Coefficients of Halomethanes."

6. S. A. Kudchadker and A. P. Kudchadker, "Enumeration of Substituted n-Alkanes."

22
List of Publications that Resulted from the Project

1. S. A. Kudchadker and A. P. Kudchadker, "Ideal Gas Thermodynamic Properties of Xenon

Compounds," Proc. Indian Acad. Sci. 73_, 261, Sec. A (1971).

2. A. P. Kudchadker, D. M. Agarwal, S. A. Kudchadker, "Ideal Gas Thermodynamic Properties

of Chlorine, Bromine, and Iodine Pentafluorides , " Indian J. of Chem. 9, 122 (1971).

23
A. 5." STANDARD REFERENCE DATA

Project Title : CRITICAL REVIEWS OF PHASE TRANSFORMATIONS IN INORGANIC SOLIDS

Principal Investigator : Professor C.N.R. Rao

Institution : Indian Institute of Technology, Kanpur

NBS Monitor : Dr. L. H. Gevantman

NBS Institute or Center and Division : Office of the Associate Director for Information

Programs , Office of Standard Reference Data

Summary Description of Project Goals

Critical reviews were to be prepared in which thermodynamic, kinetic and other important data on phase transformations of inorganic solids were to be presented in an organized

manner. The methods employed to study these transformations and changes in various properties accompanying the transformations were to be discussed. The reviews will be restricted

to simple inorganic compounds such as chlorides , sulfates , nitrates , nitrites , carbonates

,

oxides, sulfides, and so on. Such reviews are expected to be of great value to chemists,

physicists , materials scientists and others interested in the structure and properties of

materials

.

Results and Implications to Date

The following reviews have been undertaken and are in the indicated status

:

1. Crystal Structure Transformations in Binary Halides , C.N.R. Rao and M. Natarajan,

NSRDS Publication NBS 4T, 1972.

2. Transition Metal Oxides, C.N.R. Rao and G.V. Subba Rao, NSRDS publication,

in press.

3

.

Crystal Structure Transformations in inorganic carbonates , nitrates , and nitrites

,

C.N.R. Rao and B. Prakash. The first draft of this monograph is ready and will soon

be submitted for publication.

Graduate and post doctoral students who are associated with the project have spent part

of their time on research and have produced several publications based on experimental work

associated with this project. Publications are listed below.

List of Publications that Resulted from the Project

1. M. Natarajan, B. Prakash, and C.N.R. Rao, "Defect Energies in CsCl and its Solid

* The alphanumeric designation refers to the NBS Program Structure (see Appendix II).

24
Solutions with KC1, RbCl and CsBr," J. Chem. Soc. A, 1223 (1971).

2. C.N.R. Rao and M. Natarajan, "Crystal Structure Transformations in Binary Halides,"

NSRDS Publication NBS 40., 1972.

3. P. Ganguly and C.N.R. Rao, "Electron Transport Properties of Transition Metal Oxide

Systems with the K„NiF^ Structure," Materials Research Bulletin (March 1973).

25
A. 5.* STANDARD REFERENCE DATA

Project Title : INFRARED BIBLIOGRAPHY

Principal Investigator : Professor C.N.R. Rao

Institution : Indian Institute of Technology, Kanpur

NBS Monitor : Dr. L. H. Gevantman

NBS Institute or Center and Division : Office of the Associate Director for Information

Programs , Office of Standard Reference Data

Summary Description of Project Goals

This project has been planned to prepare bibliographies of infrared spectroscopic

data from the scientific literature. The material will be arranged on the basis of molecular formulae. For each compound, the empirical formula, chemical name and a list of

references ( author ' s names , j ournal reference ) will be given ; in addition , a brief

description of the region covered and the nature of information available in each of the

references will also be given. The material for the bibliographies will be taken from

standard journals and will include all those publications which deal primarily with

spectroscopy.

Results and Implications to Date

The first such bibliography has now been completed and is being typed.

List of Publications that Resulted from the Project

None

26
A. 5* STANDARD REFERENCE DATA

Project Title : STUDIES OF METAL OXIDES, PHASE TRANSITIONS AND RELATED PROBLEMS

Principal Investigator : Professor C.N.R. Rao

Institution : Indian Institute of Technology, Kanpur

NBS Monitor : Mr. H. Steffen Peiser and Dr. H. F. McMurdie

NBS Institute or Center and Division : Institute for Materials Research

Inorganic Materials Division

Summary Description of Project Goals

Phase transitions and related studies on metal oxides and other inorganic solids were

to be investigated. Some aspects of defect solids were also to be examined. The goals were

adhered to. This project terminated in December 1971.

List of Publications that Resulted from the Project

1. A. K. Shukla, S. Ramdas , and C.N.R. Rao, "Intrinsic and Extrinsic Defect Pairs in Cesium

Halides, J. Chem. Soc. Faraday II, 69_, 207 (1973).

2. S. Ramdas, A. K. Shukla, and C.N.R. Rao, "Association Energies of Intrinsic and Extrinsic Defect Pairs in KC1," Chem. Phys. Letters, 16_, 14 (1972).

3. C.N.R. Rao, S. Ramdas, R. E. Loehman, and J. M. Honig, "Semiconductor-Metal Transition

in Ti

3 5 ," J. Solid State Chem. 3_, 83 (1971).

4. G. V. Subba Rao, P. N. Mehrotra, and C.N.R. Rao, "Semiconduction in Rare Earth Oxides,"

J. Solid State Chem., 2, 377 (1970).

5. M. Natarajan and C.N.R. Rao, "Phase Transitions in Silver Halides," J. Chem. Soc.

(London), A, 3087 (1970).

6. C.N.R. Rao, G. V. Subba Rao, M. Natarajan, and R. E. Loehman, "Semiconductor-Metal

Transitions in V0

2

, Nb0

2 and Some Solid Solutions of V0„," J. Phys. Chem. Solids, 32_,

1147 (1971).

7. G. V. Subba Rao, B. Wanklyn, and C.N.R. Rao, "Electrical Transport in Rare Earth

Perovskites: Rare Earth Ortho -Chromites , -Manganites and -Ferrites," J. Phys. Chem.

Solids, 32_, 345 (1971).

8. G. V. Subba Rao, S. Ramdas, and C.N.R. Rao, "Electrical Conduction in Binary Oxides of

the Type M'

2 -M"

2 3 ," Indian J. Chem., 9_, 242 (1971).

* The alohanumeric designation refers to the NBS Program Structure (see Appendix II).

27
9. C.N.R. Rao, G. V. Subba Rao, and S. Ramdas, "Phase Transformations and Electrical

Properties of Bi 0,," J. Phys. Chem. , 73_, 672 (1969).

10. C.N.R. Rao and K. J. Rao, "Phase Transformations in Solids," "Progress in Solid State

Chemistry," Vol IV, Ed. by H. Reiss, Pergamon Press, Oxford (1967).

11. K. J. Rao and C.N.R. Rao, "Surface Energies of Alkali Halides," Indian J. Chem., 6_,

637 (1968).

12

.

Schottky Defect Energies in Alkali Halides : Their Creation , Interaction and Migration ,

Physica stat solidi, 28., 157 (1968).

13. K. J. Rao and C.N.R. Rao, "Schottky Defect Energies in Cesium Chloride," Solid State

Comm. , 6_, 45 (1968).

14. K. J. Rao, G. V. Subba Rao, and C.N.R. Rao, "Born Treatment of the Phase Transitions

of Alkali Halides Employing New van der Waals Parameters," Proc. Phys. Soc. (London),

1, 1134 (1968).

15. C.N.R. Rao, M. Natarajan, and G.V. Chandrashekhar , "Heats of Crystallization of

Amorphous Oxides," J. Chem. Eng. Data, 13_, 235 (1968).

16. K. J. Rao and C.N.R. Rao, "Melting of Ionic Solids and the Born Trealjnent," Chem. Phys

Letters, 1, 499 (1968).

17. G.V. Chandrashekhar, P. N. Mehrotra, G. V. Subba Rao, and C.N.R. Rao, "Semiconduction

of Non- Stoichiometric Rare Earth Oxides," Trans. Faraday Soc, 63_, 1295 (1967).

18. G. V. Subba Rao, G.V. Chandrashekhar , and C.N.R. Rao, "Are Rare Earth Chromites

Ferroelectric?" Solid State Comm., 6_, 177 (1968).

19. K. J. Rao and C.N.R. Rao, "Pressure Transitions of Alkali Halides and the Born Treatment," Proc. Phys. Soc. (London), 91, 754 (1967).

20. K. J. Rao, G.V. Subba Rao, and C.N.R. Rao, "Pm3m-Fm3m Transformations of CsCl and its

Solid Solutions with RbCl: Born-Meyer Treatment," Trans. Faraday Soc, 63_, 1013

(1967).

21. P. N. Mehrotra, G.V. Chandrashekhar, E. C. Subbarao, and C.N.R. Rao, "Phase Transformations of Rare Earth Sesquioxides , " Trans. Faraday Soc, 62., 3586 (1966).

22. K. J. Rao and C.N.R. Rao, "Crystal Structure Transformations of Alkali Sulphates,

Nitrates and Related Substances: Thermal Hysteresis in Reversible Transformations,"

J. Materials Sci. , 1, 238 (1966).

28
23. K. J. Rao and C.N.R. Rao, "Ferroelectric Transformation in KNCL," British J. Appl.

Phys. , 17, 1653 (1966).

24. G. V. Subba Rao, M. Natarajan, and C.N.R. Rao, "Effect of Impurities on the Phase

Transformation and Decompositions of CaC0~," J. Am. Ceramic Soc. , 51, 179 (1968).

25. M. Natarajan, T.S. Sharma, J. C. Ahluwalia, and C.N.R. Rao, "Thermal and Particle Size

Effects on MgO," Trans. Faraday Soc, 65_, 3088 (1969).

26. M. Natarajan, A.R. Das, and C.N.R. Rao, "Particle Size Effects and Thermal Hysteresis

in Phase Transformations," Trans. Faraday Soc, 65_, 3081 (1969).

27. M. Natarajan, K. J. Rao, and C.N.R. Rao, "Pm3m-Fm3m Transformations of Alkali Halides:

Solid Solutions of CsCl with KC1, CsBr and SrBr ," Trans. Faraday Soc. , 66_, 2497

(1970).

28. M. Natarajan, S. Ramdas , and C.N.R. Rao, "Antiferroelectric Transition in CsPbCl-,"

Physics Letters, 29, 528 (1969).

29. S. Ramdas, K.C. Patil, and C.N.R. Rao, "Kinetics and Thermodynamics of Oxidation of

PrO, and Tb

2 3 to Non- Stoichiometric Oxides," J. Chem. Soc. (London), (A), 6M_ (1970).

30. C.N.R. Rao and G.V. Subba Rao, "Electrical Conduction in Metal Oxides," Phys. stat.

solidi, la, 597 (1970).

Ph.D. Theses (I.I.T.-Kanpur) of Research Fellows supported by NBS(G)-51

1. K.J. Rao, "Phase Transitions and Schottky Defects in Ionic Solids," Ph.D., (1967).

2. M. Natarajan, "Phase Transitions in Solids," Ph.D., (1970).

3. S. Ramdas, "Theoretical and Experimental Studies on Defect Solids," Ph.D. (1971).

29
A. 5.- STANDARD REFERENCE DATA

Project Title: MAGNETIC PROPERTIES OF ATOMIC NUCLEI AND OF THE NUCLEAR ENVIRONMENT AND

ON THE LIFETIMES OF NUCLEAR STATES

Principal Investigator : Dr. G. N. Rao

Institution : Indian Institute of Technology, Kanpur

NBS Monitor : Dr. Lewis H. Gevantman

NBS Institute or Center and Division : Office of Associate Director for Information

Programs ; Office of Standard Reference Data

Summary Description of Project Goals

The goals of the project are:

(a) To measure the hyperfine fields induced at nuclei due to electron

polarization. These studies are expected to give better understanding

of hyperfine interactions.

(b) To measure the lifetimes of nuclear excited states and to compare

the experimental values with those predicted by the nuclear models.

These studies enable us to understand the structure of these nuclei

and also check the validity of the nuclear models

.

(c) To prepare an up-to-date table of nuclear lifetimes and compare the

evaluated values of the different multipole transitions with the

predictions of the nuclear models.

(d) To prepare an up-to-date table of hyperfine fields and also to

prepare an evaluated table for the dilute impurity hyperfine fields

in host matrices of Fe, Co, Ni, and Gd.

Results and Implications to Date

(a) Hyperfine Field Studies

Dilute impurities embedded in ferromagnetic host matrices like Fe, Co, Ni, Gd

etc . experience large internal fields . A general Hamiltonian of the impurity

atom is quite complicated and therefore a formal solution of the impurity problem

is difficult. Studies of the systematics [1] of these hyperfine fields as

a function of the electronic configuration of the impurity resulted in useful

* The alphanumeric designation refers to the NBS Program Structure (see Appendix II),

Figures in square brackets indicate the publication reference at the end of this project review.

30
information about the possible mechanisms resDonsible for the electron polarization at the nucleus. So far we have measured the hyoerfine fields on Sc in

Fe, Re in Ni and Sc in Co, using the (Y-Y) perturbed angular correlation

technique. These experimental values are compared with the existing models.

An automatic electromechanical Mossbauer svstem and a low temperature

liquid helium cryostat were designed and fabricated. The Mossbauer apparatus

will be used for the hyperfine field measurements in alloys

.

(b) Nuclear Lifetime Measurements

Using the delayed coincidence techniques the short nuclear lifetimes

in 44c 75. 99„ 131„ 133„ 17CU 181_ 187„ and 197. were measured

Sc , As , Ru , Cs , Cs , Yb , ra , Re , Au

and compared with the predictions of the nuclear models

.

(c) Nuclear Lifetimes Table

We have prepared a complete "Nuclear Lifetimes Table" wherein we have

tabulated all the experimental values so far reported on the lifetimes of

nuclear ground and excited states. All the data were processed with the help

of a computer. Computer programs were developed to obtain the output with

different options like increasing Z, increasing A, and increasing energy.

Using this table another "nuclear lifetimes table" is being prepared with

evaluated values. The evaluated values will be used for comparing the

experimental transition rates with the single particle estimates. Comparisons

with more realistic models are also planned.

(d) Table of Hyperfine Fields

A general table of hyperfine fields was prepared wherein all the values

reported so far in the literature were tabulated. The data were processed

with the help of a computer.

In order to study the systematics in general of the dilute impurity

hyperfine fields in the host matrices of Fe, Co, Ni, and Gd all the experimental data available in the literature were collected and tabulated separately.

Where multiple measurements exist, recommended or evaluated values were given.

The impurity hyperfine field values plotted as a function of the electronic

configuration of the impurity showed very definite and systematic trends.

31
These values are being compared with the existing models

.

In addition to the publications mentioned in the following section, four papers are

in an advanced stage of preparation:

1. "Nuclear Lifetimes Table" wherein all the values reported so far are listed.

This will be brought out in a couple of months as a report of about 450 pages

.

The rough manuscript is ready.

2. "Evaluated Nuclear Lifetimes Table" wherein recommended values are given.

This will be ready in a couple of months.

3. "Hyperfine Fields Table" wherein all the values reported so far are listed.

The rough manuscript is ready and will be published soon.

4. "Dilute Impurity Hyperfine Fields" in Fe, Co, Ni, and Gd. Here the recommended

values for the dilute impurities in the host matrices of Fe, Co, Ni, and Gd are

given. The manuscript is ready and will be sent for publication soon.

References

:

1. D. A. Shirley, S. S. Rosenblum, and E. Matthias, Phys. Rev. 170 , 363 (1968).

List of Publications that Resulted from the Project

1. D. K. Gupta, C. Rangacharyulu , R. Singh, and G.N. Rao, "Nuclear Level Studies of

99 Ru," Nucl. Phys. A180 311 (1972).

2. D. K. Gupta and G.N. Rao, "Nuclear Lifetime Measurements of Some Excited States in

75As,

131

Cs,

133

Cs,

170Yb, 187

Re, and 197

Au," Nucl. Phys. A182 669 (1972).

3. D. K. Gupta, A. K. Singhvi, D. N. Sanwal, and G. N. Rao, "Hyperfine Field Measurements

on Sc in Fe and Re in Ni." Accepted for publication in Phys. Rev. B_ Solid State

Physics, ITT, Technical Report No. 20/72.

4. A. K. Gupta, K. R. Sarma, J. J. Huntzicker, T. M. Srinivasan, and G. N. Rao, "Design

and Fabrication of a Mossbauer Spectrometer and a Low Temperature Cryostat." Sent to

Nucl. Instr. and Meth. , IIT, also published as LET, Technical Report No. 5/72.

5. A. K. Singhvi, D. K. Gupta and G. N. Rao, "Timing Properties of Ge(Li) Detector,"

accepted for publication in J. of Phys. Soc. , Japan, Proc. of the Nucl. Phys. and

Solid State Phys. Symposium, 555 (Feb. 1972).

32
6. A. K. Singhvi, D, K. Gupta, and G.N. Rao, "Hyperfine Field Measurements on Sc in Co,"

submitted for presentation at Nucl. Phys. and Solid State Phys. Symposium Dec. 1973

(to be published).

7. B. V. N. Rao, A. K. Singhvi, and G. N. Rao, "Decay of 49 Cr (41 min) and 189W (11 rain),"

submitted for presentation at Nucl. Phys. and Solid State Phys. Symposium Dec. 1973

(to be published).

8. D. K. Gupta, D. N. Sanwal, and G. N. Rao, "Lifetime and Magnetic Moment of 68 KeV State

44 in Sc," Nuclear Phys. and Solid State Phys. Symposium (1971).

9. P. A. Narayana, T. M. Srinivasan, G. N. Rao, and P. Venkateswarlu , "Electron Paramagnetic Resonance Studies of Divalent Manganese in Ammonium Bromide Single Crystals ,

Nuclear Phys. and Solid State Phys. Symposium 1970 (to be published).

33
A. 5.* STANDARD REFERENCE DATA

Project Title : INVESTIGATIONS ON MOLECULAR SPECTRA

Principal Investigator : Professor Nand Lai Singh

Institution : Banaras Hindu University, Varanasi

NBS Monitor : Dr. A. Bass

NBS Institute or Center and Division : Institute for Materials Research

Physical Chemistry Division

Summary Description of Project Goals

This scheme was undertaken with a view to investigate the spectra of diatomic and

polyatomic molecules in the visible, near ultraviolet, and near infrared regions.

Results and Implications to Date

The NBS PL-480 grant provided for the scheme has generally added greatly to the

facilities and scope of the Laboratory. The grant received has been utilized in designing

and constructing appropriate sources for emission of radiation and in procuring some

useful instruments which could not have been procured through normal grants.

The facilities that have been created greatly assist in furthering research and training

programs . Fellowships have been awarded to several research scholars who have secured

Ph.D. degrees.

1. Rotational and Vibrational Structure of the Electronic Spectra of Diatomic Molecules :

Extensive studies have been made in the structure of electronic spectra of diatomic

molecules using a 35 ft. concave grating spectrograph. Ran B. Singh, B.S. Mohanty,

K.N. Upadhya, D. K. Rai , and N. L. Singh studied the rotational structure of PO 3-system

from plates taken on 35 ft. grating spectrograph. These studies have resulted in accurate

2 2 determination of rotational and vibrational constants for the B E and X n states in the

PO molecule. The peculiar feature of reversal of shading in these bands has been explained.

The calculation of the Franck-Condon factors and the potential energy curves for several

states have been accomplished.

121 123 The rotational analyses of the B-X system of SbO and SbO have been made more

accurately than before by Ran B. Singh and K.N. Upadhya. The isotope effect has been

detected for the first time in the spectra of this molecule. The D-X system in the spectrum

of SbO has also been analyzed.

- The alphanumeric designation refers to the NBS Program Structure (see Appendix II),

34
Studies of the electronic spectra of BiCl and BiF have been carried out in great

detail. The rotational analyses of the A-X systems of the two molecules have been

extended and the A'-X system of BiCl and C-X systems of BiF have been analyzed for the

first time.

The analysis of the C-X system of BiF given by B. S. Mohanty and A. K. Choudhary

3 involves forbidden transitions from (a) H to singlet lower states.

The analysis of the rotational structure of A-X and B-X systems of CaF is also new

and though large spin doubling and small sequence separations made the analyses quite

difficult, useful constants have been derived. The isotope effect has been used to

reanalyze the vibrational structure of the SrCl bands

.

2. Investigations of Electronic and Vibrational Spectra of Substituted Benzenes :

The number of molecules studied under this heading is too large to be enumerated.

The results obtained are backed by data which have formed the basis of several publications

listed below. We have succeeded in analyzing the vibrational structure in the electronic

spectrum of several such molecules. One interesting aspect of these studies has been the

study of the emission spectra in the presence of flowing vapor of benzene. In several

cases this has resulted in the excitation of singlet-triplet transitions in the vapor

phase, which is well-nigh impossible otherwise. Another interesting investigation has

been the study of hydrogen bonding in derivatives of quinone.

A new line of investigation was started by Dr. S.N. Thakur who studied the absportion

spectra of several para fluorinated benzenes under the high resolution obtainable in the

third order from the 35 ft. grating. He succeeded in resolving the K-structure. This

structure was analyzed on the basis of the symmetric top approximation and thus yielded

approximate rotational constants for the upper electronic state. The accuracy of measurement of the structure has been very recently demonstrated clearly by more detailed calculations of Dr. Hollas of Reading University, England.

In this project the Indian group succeeded in making some contributions to a basic

aim of the National Bureau of Standards ; providing reliable data for science and technology.

The NBS project monitor, Dr. A. M. Bass, has been examiner of some of the Ph.D. theses from

this Laboratory.

35
List of Publications that Resulted frcm the Project

Although this project was operative only from 1963 to 1968 inclusive, the output of results

and scientific publication continued well beyond the formal termination of the grant.

(Only a partial list is here given because of the large number of publications.)

Spectra and Structure of Diatomic Molecules

1. K.P.R. Nair, Ran B. Singh, and D. K. Rai, "Potential Energy Curves and Dissociation

Energies of Oxides and Sulfides of IVA Group Elements," J. Chem. Phys. 45, 3570 (1965).

2. K.P.R. Nair and K.W. Upadhya, "E-X Band System of Copper Iodide Molecule," Nature 211 ,

1170 (1966).

3. K.P.R. Nair and K.N. Upadhya, "Rotational Analysis of the D-X System of Cul Molecule,"

Current Sci. (India) 35, 593 (1966).

4. K.P.R. Nair and K.N. Upadhya, "Rotational Analysis of the E-X and C-X band Systems of

Cul Molecule," Can. J. Phys. 44, 1267 (1966).

5. Ran B. Singh and D. K. Rai, "Potential Energy Curves of O^, N

2 and CO ," J. Mol.

Spectry. 19, 424 (1966).

6. Ran B. Singh and K.N. Upadhya, "Visible Bands of the BiCl Molecule," Current Sci.

(India) 35_, 484 (1966).

7. Ran B. Singh and D. K. Rai, "Potential Curves of some Diatomic Molecules, P„, PN, SiN,

NBr, BaO, BeF, SiF and SnF," Indian J. Pure and Appl. Phys. 4, 102 (1966).

8. K.P.R. Nair and K.N. Upadhya, "The A-X Band System of the Copper Chloride Molecule,"

Current Sci. (India) 36_, 399 (1967).

9. D.V.R.A. Rao, K.P.R. Nair, and D.K. Rai, "Franck-Condon Factors and r-Centroids of the

new 2 *-X^

+ Band System of A10," Current Sci. (India) 36, 604 (1967).

10. K.P.R. Nair and D.K. Rai, "On the Internuclear Distance of Cul," Can. J. Phys. 45_,

2810 (1967).

11. B.S. Mohanty and K.N. Upadhya, "Rotational Analysis of some Visible Bands of the BiF

Molecule," Current Sci. (India) 36_, 478 (1967).

12. B. S. Mohanty, K.N. Upadhya, Ran B. Singh, and N.L. Singh, "On the 6-Band System of the

P0 Molecule," J. Mol. Spectry. 7M_, 19 (1967).

13. D.K. Rai and B.S. Mohanty, "Franck-Condon Factors and r-Centroids of the Cl-X System of

the P0 Molecule," Current Sci. (India) 36, 231 (1967).

36
14 • B.S. Mohanty and K.N. Upadhya, "A-X and B-X Band Systems of the CaF Molecule," Indian

J. Pure and Appl. Phys. 5_, 23 (1967).

15. S.N. Thakur and R.B. Singh, "Potential Curves and Bond Strength of CP, BeO and MgO,"

J. Sci. Res. (B.H.U.) 18, 253 (1967-68).

16. D.K. Rai and J.L. Calais, "A Simple AMO Function for the Lithium Molecule," J. Chem.

Phys. 47, 906 (1967).

17. R.K. Pandey, K.N. Upadhya, and B.S. Mohanty, "Rotational Analysis of the A-X System

of Cul Molecule," Indian J. Phys. 42_, 154 (1968).

18. D.V.R.A. Rao, K.P.R. Nair, Ran B. Singh and D.K. Rai, "On the Potential Energy Curves

of Diatomic Copper Halides," Indian J. Phys. 41, 205 (1968).

19. S.N. Thakur, D.K. Rai, and N.L. Singh, "Zeeman Effect in the (0,0) Band of 0D,"

J. Chem. Phys. 48, 3389 (1968).

20. O.N. Singh and I.S. Singh, "Rotational Analysis of the A-X Bands of PbCl Molecule,"

Current Sci. (India) 37_, 282 (1968).

21. A.K. Chaudhary, K.N. Upadhya, D.K. Rai, and B.S. Mohanty, "Rotational Structure of the

3050-3250 A System of the BiF Molecule," J. Phys. B. (Proc. Phys. Soc. ) 1, 1223 (1968).

22. B.S. Mohanty, D.K. Rai, and K.N. Upadhya, "Structure and Analysis of some Bands of the

g-System of the P0 Molecule," Proc. Indian Acad. Sci. 68_, 165 (1968).

23. B.S. Mohanty, D.K. Rai, K.N. Upadhya, and N.L. Singh, "Rotational Structure of the

2650-2850 A System of the BiF Molecule," J. Phys. B. (Proc. Phys. Soc.) 1, 523 (1968).

24. D.V.R.A. Rao, K.P.R. Nair, and D.K. Rai, "Vibrational Transition Probabilities and

r-Centroids of Diatomic Molecules; Band Systems of CuCl," Indian J. Pure £ Appl.

Phys. (5_, 396 (1968).

25. S.N. Thakur, R.B. Singh, and D.K. Rai, "Potential Energy Curves and Nature of Binding

in Group IIIA Monohalides , " J. Sci. S Indust. Res. 27, 339 (1968).

26. O.N. Singh and I.S. Singh, "Rotational Analysis of 6-Bands of SiF," Current Sci.

(India) 37, 3 (1968).

27. B.S. Mohanty, K.P.R. Nair, and K.N. Upadhya, "Rotational Analysis of the Bands of the

A'-X System of the BiCl Molecule," Indian J. Pure £ Appl. Phys. 6_, 494 (1968).

28. A. K. Chaudhary, K.N. Upadhya, and D.K. Rai, "Rotational Structure of the 2250A

System of the BiF Molecule," J. Phys. B. (Atom. £ Mol. Phys.) 2_, 628 (1969).

37
29. B.S. Mohanty and O.N. Singh, "Franck-Condon Factors and r-Centroids of seme Band

Systems of the Monofluorides of Silicon, Calcium and Bismuth," Indian J. Pure £

Appl. Phys. 7_, 109 (1969).

30. S.N. Thakur, K.P.R. Nair, and D.K. Rai, "Chemical Bonding in the Low Lying Electronic

States of Copper Halides," Indian J. Pure £ Appl. Phys. 7_, 529 (1969).

31. S.N. Thakur and Ran B. Singh, "Potential Energy Curves for some Astral Radicals,"

J. Sci.Res. B.H.U. 20(2) , 58 (1969-70).

32. O.N. Singh, M.P. Srivastava, and I.S. Singh, "Rotational Analysis of A-X Bands of

PbF," Can. J. Phys. k]_, 1639 (1969).

33. R. Sharker, I.S. Singh, and O.N. Singh, "Rotational Analysis of A-X Bands of AsO ,"

Can. J. Phys. 47, 1601 (1969).

34. A. K. Chaudhary, K. N. Upadhya, "On the Transition A1C1 Molecule," Indian J. Phys.

42, 544 (1968).

35. J. Singh, K.P.R. Nair, and D.K. Rai, "Electronegativity Potential Energy Curves for

Diatomic Molecules," J. Mol. Structure _5, 492 (1970).

36. J. Singh, K.P.R. Nair, and D.K. Rai, "Dissociation Energy of Diatomic Halides of

Boron and Aluminum," J. Mol. Structure 5_, 600 (1970).

37. Jagadish Singh, K.P.R. Nair, and D.K. Rai, "Dissociation Energy, Franck-Condon Factors

and r-Centroids of the Diatomic BiCl Molecule," Indian J. Pure £ Appl. Phys. 8_, 614

(1970).

38. K.P.R. Nair and K.N. Upadhya, "New Bands in the Emission Spectrum of CuBr," J. Sci.

Res. B.H.U. 20(2) , 173 (1969-70).

39. B. Rai, K.N. Upadhya, and D.K. Rai, "Rotational Analysis of the D-X System of the

SbO Molecule," J. Phys. B. (Proc. Phys. Soc.) 3_, 1374 (1970).

40. P.S. Dube, K.N. Upadhya, and D.K. Rai, "Intensity Distribution in the B-X System of

PbO," J. Quant. Spect. Rad. Trans. 11, 1191 (1970).

41. Jagadish Singh, K.P.R. Nair, K.N. Upadhya, and D.K. Rai, "On the Red Bands of the

SrCl Molecule," Opt. Pura y Aplicada 3_, 3 (1970).

42. P.S. Dube, K.P.R. Nair, K.N. Upadhya, and N.L. Singh, "Determination of the Vibrational

Temperature of the CN Violet Band System from the Benzonitrile Discharge," Indian J.

Pure £ Appl. Phys. 8_ (1970).

38
43. A. K. Choudhary, K.N. Upadhya, and K.P.R. Nair, "Isotope Shift in the B-X Band System

of the S

2 Molecule," Indian J. Pure S Appl. Phys. _8 52 (1970).

Spectra and Structure of Polyatomic Molecules

44. R.B. Singh and D.K. Rai, "Valance Force Constants of MoF , TeFg and ReF '' Can. J.

Phys. 43_, 167 (1965).

45. O.N. Singh and D.K. Rai, "The Mean Square Amplitude of Interatomic Distances in some

Octahedral Hexafluoride Molecules , " Can. J. Phys. 43_, 373 (1965).

46. R.D. Singh and R.S. Singh, "Emission and Absorption Spectrum of 8-Methylnaphthalene

Vapor," Indian J. Pure & Appl. Phys. 4, 89 (1966).

47. R. N. Singh, "Emission Spectrum of Styrene Vapor," Indian J. Pure £ Appl. Phys. 4_,

1 (1966).

48. V.B. Singh and I.S. Singh, "Longest Wavelength If-H Electronic Absorption Spectra of

o- and m-Tolualdehydes," J. Mol. Spectry. 20, 282 (1966).

49. M.G. Jayswal and R.S. Singh, "Triplet-Singlet Emission of p-Quinones in the Vapor

Phase," Proc. Int. Con. on Luminescence P. 357 (1966).

50. G. Joshi and N.L. Singh, "Infrared Spectrum of o-Bromotoluene , " Spectrochim. Acta 22 ,

1501 (1966).

51. P.K. Verma and N.L. Singh, "Emission Spectrum of o-Fluoroaniline in the Near Ultraviolet Region," Current Sci. (India) 35, 145 (1966).

52. S.N. Thakur and D.K. Rai, "Force Constants of Metal Hexafluorides , " J. Mol. Spectry.

19, 341 (1966).

53. S. N. Singh and N.L. Singh, "Near Ultraviolet Absorption Spectrum of 2 , 5-Dichloroaniline in the Vapor Phase," Current Sci. (India) 35_, 62 (1966).

54. R. D. Singh and R.S. Singh, "Near Ultraviolet Absorption Spectrum of a-Chloronaphthalene Vapor," Indian J. Pure S Appl. Phys. 4, 263 (1966).

55. 11-11 Absorption Spectrum of Anthraquinone in the Vapor State," Indian J. Pure & Appl.

Phys. 5_, 245 (1967).

56. M.P. Srivastava and I.S. Singh, "The n- H Electronic Absorption Spectrum of mFluorobenzaldehyde in the Vapor Phase," Current Sci. (India) 36_, 456 (1967).

57. M.P. Srivastava and I.S. Singh, "Emission Spectra of o-m and p-Fluorobenzaldehydes ,

Current Sci. (India) 36_, 399 (1967).

39
58. S. Nath Singh and R.S. Singh, "Emission Spectrum of 1-Methyl 9 ,10-Anthraquinone Vapor,"

Current Sci. (India) 36_, 483 (1967).

59. S. Nath Singh, M.G. Jayswal, and R.S. Singh, "Vibrational Spectrum of Acenaphthenequinone," Current Sci. (India) 36, 624 (1967).

60. V.B. Singh and I.S. Singh, "Vibrational Spectra of o-, m- and p-Fluoro-and Bromobenzaldehydes , " Current Sci. (India) 36_, 365 (1970).

61. V.B. Singh, "Infrared Spectrum of p-Bromoanisole , " Current Sci. (India) 36_, 427 (1967).

62. V.B. Singh and I.S. Singh, "n-H Absorption Spectra of o-m- and p-Tolualdehydes in the

Vapor Phase," Current Sci. (India) 36, 603 (1967).

63. O.N. Singh, M.P. Srivastava, and I.S. Singh, "Infrared Spectra of Salicylaldehydes ,

Current Sci. (India) 36, 630 (1967).

64. G.D. Baruah and R.S. Singh, "Spectra of 1 , 4-Dihydroxyanthraquinone in the Infrared

and Optical Region," Current Sci. (India) 3&, 503 (1967).

65. S. Nath Singh and R.S. Singh, "Sensitized Emission Spectrum of 9 ,10-Anthraquinone

in the Visible Region," Indian J. Pure & Appl. Phys. _5, 342 (1967).

66. S. N. Singh and R.S. Singh, "Visible Emission Spectrum of 1 , 4-Naphthoquinone , " Indian

J. Pure g Appl. Phys. 5, 394 (1967).

67. S.N. Singh and R.S. Singh, "Near Ultraviolet Absorption Spectrum of 2-Methyl, 1-4-

Naphthoquinone Vapor," Indian J. Pure S Appl. Phys. 5_, 430 (1967).

68. O.N. Singh, M.P. Srivastava, and I.S. Singh, "Vibrational Spectrum of the Cinnamaldehyde Molecule," J. Sci. Res. B.H.U. 17_, 165 (1967).

69. G.D. Baruah, O.N. Singh, and M.P. Srivastava, "Infrared Spectra of m- and p-Hydroxybenzaldehydes," J. Sci. Res. B.H.U. 18, 200 (1967).

70. The n- H Electronic Absorption Spectra of o- and p-Fluorobenzaldehydes , " J. Sci. Res.

B.H.U. 17(1) , 252 (1967).

71. V.B. Singh and I.S. Singh, "Infrared Spectra of p-Bromoanisole," J. Sci. Res. B.H.U.

17(2) , 203 (1966-67).

72. V. B. Singh and I.S. Singh, "Vibrational Spectra of Three Isomeric Nitrotoluenes ,

J. Sci. Res. B.H.U. 17(2) , 203 (1966-67).

73. G. Thakur and K.P.R. Nair, "The Vibrational Overlap Integrals and Relative Band

Intensities in the Spectra of Cul and CuF," J. Sci. Res. B.H.U. 17, 260 1967).

40
74. K.P.R. Nair, R. Amini Amma, and S. Nath Singh, "Infrared Spectrum of 1-Fluoroanthraquinone," J. Sci. Res. B.H.U. 18, 204 (1967).

75. V.B. Singh and I.S. Singh, "Vibrational Spectra of the Three Isomeric Tolualdehydes ,

Indian J. Pure £ Appl. Phys. 6_, 682 (1968).

76. Jaya V. Shukla, V.B. Singh, and K.N. Upadhya, "Vibrational Spectra of Three Isomeric

Dinitrobenzenes," Indian J. Phys. 42, 511 (1968).

77. M.P. Srivastava, O.N. Singh, and I.S. Singh, "Vibrational Spectra of o-, m- and pMethoxybenzaldehydes , " Current Sci. (India) 37_, 100 (1968).

78. D.V.R.A. Rao and D.K. Rai, "Force Constants and Thermodynamic Properties of Garmylacetylene," Current Sci. (India) 37, 41 (1968).

79. K. Singh and V.B. Singh, "Infrared Absorption Spectrum of 3-Bromostyrene," Current Sci.

(India) 37_, 525 (1968).

80. S.N. Singh and I.S. Singh, "Near Ultraviolet Emission Spectrum of m-Difluorobenzene ,

Indian J. Phys. 42, 42 (1968).

81. M.P. Srivastava, O.N. Singh, and I.S. Singh, "Infrared Spectrum of p-Fluorostryrene ,

Indian J. Pure g Appl. Phys. 6_, 519 (1968).

82. S. Nath Singh and R.S. Singh, "Absorption Spectrum of 1 , 4-Naphthoquinone in the Vapor

Phase," Indian J. Pure £ Appl. Phys. 6_, 187 (1968).

83. S. Nath Singh and R.S. Singh, "Infrared Spectra of some Chloroanthraquinone Derivatives," Indian J. Pure S Appl. Phys. 6_, 454 (1968).

84. K. N. Upadhya, "The Near Ultraviolet Emission and Absorption Spectra of D-Chlorophenol," Indian J. Pure £ Appl. Phys. 6_, 344 (1968).

85. S. K. Tiwari and K. N. Upadhya, "Infrared Absorption and Ultraviolet Emission Spectra

of p-Fluoroaniline , " Indian J. Pure £ Appl. Phys. _6, 698 (1968).

86. G. Thakur, S. Nath Singh, and N. L. Singh, "Infrared Absorption Spectrum of 1-

(ChloromethvD Naphthalene," Indian J. Pure £ Appl. Phys. 6_, 575 (1968).

87. S.Nath Singh, K.P.R. Nair, and R.S. Singh, "Thermodynamic Properties of Some

Condensed Ring Quinones," Indian J. Pure £ Appl. Phys. 7_, 52 (1969).

88. J. Ladik, D.K. Rai, and K. Appel, "Semiempirical SCFLCAO Crystal Orbital Calculation

of the Energy Band Structure of the Bohopolynucleotides , " J. Mol. Spectry. 27, 72

(1968).

41
89. K.P.R. Nair, "Near Ultraviolet Spectra of 1-Chloroanthraquinone , " Current Sci. (India)

37, 1919 (1968).

90. V. B. Singh and I.S. Singh, "Vibrational Spectra of Three Bromobenzaldehydes , " Indian

J. Pure £ Appl. Phys. 6_, 682 (1968).

91. R. Amini Amma and M. Sakuntala, "Breakdown in Thermal Plasma," Indian J. Phys. 41, 208

(1968).

92. G. Thakur and K.N. Upadhya, "Electronic Spectra of 2 ,4-Dichlorotoluene," Current Sci.

(India) (1968).

93. M. P. Srivastava, O.N. Singh, and I.S. Singh, "Vibrational Spectra of Isomeric

Ethylphenole," J. Sci. Res. B.H.U. 19, (1968-69).

94. S. N. Singh and N. L. Singh, "Infrared Absorption Spectra of o- and m-Chlorotoluenes ,"

Indian J. Pure £ Appl. Phys. _6, 488 (1968).

95. G. D. Baruah, 0. N. Singh, and R. S. Singh, "Emission Spectra of m- and p-Hydroexybenzaldehydes," Indian J. Pure £ Appl. Phys. 7_, 352 (1968).

96. S. Nath Singh, G. D. Baruah, and K.P,R. Nair, "Infrared and Visible Emission Spectra of

2-Chloroanthraqui none , " Indian J. Pure £ Appl. Phys. 7_, 133 (1969).

97. D. N. Tripathi, D. K. Rai, and P. Tiwari, "On the Atomic Shell Structure in Ionization

Cross Section," Phys. Letters 28A , 757 (1969).

98. Prabhakar Tiwari, D. K. Rai, and M. L. Rustgi, "Maximum Ionization Cross Section of

Atoms," J. Chem. Phys. _50, 3040 (1969).

99. D. N. Tripathi, Prabhakar Tiwari, and D. K. Rai, "Diamagnetic Susceptibility of

Molecules Using One-Centre Wave-Functions , " Indian J. Pure £ Appl. Phys. ]_, 707 (1969).

100. D.V.R.A. Rao and D. K. Rai, "Force Constants of Some ZX YW Molecules as Calculated by

the Urey-Bradly Force Fields: GeH

3 CN, GeDgCN, SiHgCN, SiDgCN," Indian J. Pure £ Appl.

Phys. 7_, 276 (1969).

101. D.V.R.A. Rao and D. K. Rai, "Application of Urey-Bradly Force Field to some Tetrahedral

XY^ Type Molecules and Ions," Indian J. Pure £ Appl. Phys. 7, 277 (1969).

102. S. N. Thakur and S.K. Tiwari, "High Resolution Studies in the Near Ultraviolet Spectrum|

of p-Fluorophenol , " Indian J. Pure £ Appl. Phys. ]_, 570 (1969).

103. R. Amini Amma, K.P.R. Nair, and D.K. Rai, "Infrared Spectra of Pentafluorotoluene ,

Indian J. Pure £ Appl. Phys. ]_, 519 (1969).

4?
104. G.D. Baruah, K.P.R. Nair, and D.K. Rai, "Emission Spectrum of 2-Methyl Anthraquinone ,

Indian J. Pure S Appl. Phys. 7_, 520 (1969).

105. R. Amini Amma, G.D. Baruah, and K.P.R. Nair, "Near Ultraviolet Absorption Spectrum

of p-Phentidine," Indian J. Pure £ Appl. Phys. 7_, 518 (1969).

106. S. N. Singh and N.L. Singh, "Infrared Absorption Spectra of 2-Fluoro- , 2,5 Difluoroand 2,5- and 2 ,6-Dichloroanilines," Indian J. Pure S Appl. Phys. ]_, 250 (1969).

107. G.D. Baruah, S. Nath Singh, and R.S. Singh, "Vibrational and Electronic Spectra of

Naphthazarin," Indian J. Pure £ Appl. Phys. ]_, 283 (1969).

108. R. Amini Amma, K.P.R. Nair, and D.K. Rai, "Height of the Potential Barrier in Phenol,"

Indian J. Pure S Appl. Phys. 7_, 443 (1969).

109. G.D. Baruah, K.P.R. Nair, and B.B. Lai, "n-ll" Emission Spectrum of 2-Hydroxyanthraquinone," Indian J. Pure £ Appl. Phys. 7_, 713,(1969).

110. G.D. Baruah, S. Nath Singh, and R. S. Singh, "Electronic Spectra of 1,4 ,5 ,8-Tetrahydroxynanthraquinone , " Indian J. Pure £ Appl. Phys. 7_, 281 (1969).

111. Kamalesh Singh, S. Nath Singh, and D.K. Rai, "Vibrational Spectra of Condensed Ring

Aldehydes, a and g Naphthaldehydes , 9 -Anthraldehyde and 9-Phenanthraldehyde,"

Indian J. Pure £ Appl. Phys. 7_, 649 (1969).

112. R. Amini Amma, K.P.R. Nair, and S. Nath Singh, "Infrared and Electronic Absorption

Spectra of Quinoline," Indian J. Pure £ Appl. Phys. 7_, 567 (1969).

113. J.V. Shukla and K. N. Upadhya, "Raman Spectra of the Three Isomeric Dinitrobenzenes ,

Indian J. Pure £ Appl. Phys. 7_, 830 (1969).

114. J. V. Shukla, K.N. Upadhya, and D..Rai, "Thermodynamic Calculations for the Three

Isomeric Fluorochlorobenzenes , p-Fluorobromobenzene , p-Fluoroiodobenzene , " J.Sci.

Res. B.H.U. 19(1) , (1969).

115. J. V. Shukla, K.N. Upadhya, and K.P.R. Nair, "Vibrational Spectra of 2-Chloro4-Amino and 4-Chloro- 2-Amino Anisoles," J. Sci. Res. B.H.U. 20(2) , 84 (1969-70).

116. C. L. Khetrapal and D.K. Rai, "Pariser-Parr-Pople type SCF-M0-CI , Calculations on

Penta-fluorobenzenes," Theor. Chem. Acta. 13, 309 (1969).

117. K.P.R. Nair, R. Amini Amma, and M.P. Srivastava, "Infrared and Electronic Absorption

Spectrum of acta -Trichlorotoluene , " Appl. Spectry. 23, 549 (1969).

43
118. R. Amini Amma, G.D. Baruah, and K.P.R. Nair, "Electronic Absorption Spectrum of

m-Aminobenzotrifluoride Vapor," Indian J. Pure g Appl. Phys. 7_, 520 (1969).

119. A. N. Singh and I.S. Singh, "The Emission Spectrum of Benzyl Radical," Indian J.

Pure £ Appl. Phys. 7, 349 (1969).

120. S. N. Thakur and N.L. Singh, "Shape of p-Difluorobenzene Molecule in B„ Electronic

State," Indian J. Pure g Appl. Phys. 7_, 570 (1969).

121. S. N. Thakur and K.N. Upadhya, "High Resolution Studies in the near Ultraviolet

Spectrum of p-Fluorochlorobenzene , " J. Mol. Struct. % 459 (1969).

122. D. N. Tripathi and S. N. Thakur, "Kinematic Evaluation of Force Constants; Application

to Boron Trihalides," J. Mol. Struct. 5, 345 (1970).

123. S. N. Thakur and Ran B. Singh, "Potential Energy Curves for some Astral Radicals,"

J. Sci. Res. B.H.U. 20(2) , 58 (1969-70).

124. S. N. Thakur and S.N. Rai, "Kinematic Evaluation of Force Constants, Application to

Trihalides of Phosphorus and Arsenic," Austr. J. Chem. 23_, 881 (1970).

125. B. B. Lai, S. R. Singh, I. S. Singh, and M. P. Srivastava," Indian J. Pure £ Appl.

Phys. _8, 117 (1969).

126. M. P. Srivastava, 0. N. Singh, and I.S. Singh, "Infrared Spectrum of o- ,m- and

p-Nitrobenzaldehydes , " Indian J. Pure g Appl. Phys. 7_, 504 (1969).

127. S. N. Thakur, D.V.R.A. Rao and D.K. Rai, "Force Constants of XY Type Molecular Ions,"

Indian Acad. Sci. 71, 42 (1970).

128. P. C. Mishra, D. K. Rai, "PPP Calculation on Homosubstituted Benzenes," Indian J. Pure

g Appl. Phys. 8_, 70 (1970).

129. R. Amini Amma, G. D. Baruah, and K.P.R. Nair, "Electronic Absorption Spectra of 2,4-

Dimethyl Phenol," Indian J. Pure g Appl. Phys. (March 1970).

130. R. Amini Amma, K.P.R. Nair, and D. K. Rai, "Raman and Infrared Spectra of 2,5-Dichlorotoluene," Indian J. Pure g Appl. Phys. 8_, 115 (1970).

131. M. P. Srivastava and I.S. Singh, "n-u" Electronic Emission and Absorption Spectra of

o-Fluorobenzaldehyde in the Vapor Phase," J. Appl. Spectry. 24_, (Jan. Feb. 1970).

132. M. P. Srivastava, O.N. Singh, and I.S. Singh, "n-ir" Electronic Spectrum of o-Methoxybenzaldehyde Vapor," Bull. Chem. Soc. Japan, 43, 32 (1970).

44
133. V.N. Verma and D.K. Rai, "Vibrational Spectra of Isomeric Aminophenols ,

Appl. Spectry. 24, 445 (1970).

134. P.C. Mishra and D. K. Rai, "Excited State Properties of some Substituted Benzenes,"

J. Mol. Struct. 6_, 246 (1970).

135. S. N. Thakur, D.V.R.A. Rao, and D. K. Rai, "Extremal Properties of Force Constants,"

Indian J. Pure & Appl. Phys. 8_, 196 (1970).

136. R. Amini Amma, K.P.R. Nair, and D.K. Rai, "Electronic Absorption Spectrum of

Benzylchloride Vapor," Appl. Spectry. 23_, 616 (1969).

137. R. Amini Amma, S. N. Thakur, and K.P.R. Nair, "Infrared and Electronic Absorption

Spectra of Isoquinoline , " Appl. Spectry. 24_, 314 (1970).

138. R. Amini Amma, K.P.R. Nair, and D.K. Rai, "Vibrational and Electronic Spectra of

2,5-Dichlorotoluene," J. Sci. Res. B.H.U. 20(2) , 25 (1969-70).

139. S. Nath, G.D. Baruah, and D. N. Tripathi, "Raman and Infrared Spectrum of

Phenanthrenequinone," Current Sci. (India) 39, 405 (1970).

45
A. 5.- STANDARD REFERENCE DATA

Project Title : THE INVESTIGATION OF THE DECAY OF EVEN-EVEN NUCLEI IN THE MEDIUM

WEIGHT REGION

Principal Investigator : Professor P. N. Trehan

Institution : Panjab University, Chandigarh

NBS Monitor : Dr. R. S. Caswell

NBS Institute or Center and Division : Institute for Basic Standards

Center for Radiation Research

Summary Description of Project Goals

In the medium atomic weight range the behavior of the energy levels of the nuclei

with even numbers of protons and neutrons is characterized by a vibration like sequence

of levels with spins of , 2 , or 4 for the second excited state. The ratio of the

energies of the second to the first excited state lies between 1 . 8 and 2.5.

It was proposed to investigate such behavior in detail for certain medium-weight and

even-even nuclei. This project meant setting up the following well known facilities for

nuclear spectrometry:

1. Single-crystal spectrometer

2. Gamma-gamma and beta-gamma scintillation spectrometer

3. Angular correlation table

4. Sum spectrometer

5. Coincidence sum spectrometer (Hoogenboom type)

6

.

Beta-ray magnetic spectrometer

The measurements with some of this equipment would permit the measurement of the

frequency and intensity of the various radiations observed in the decay of a nuclide

under investigation and in turn help in the clarification of the relevant decay scheme.

The gamma-gamma angular correlation studies , wherever possible , would give the value

of 6, the mixing ratio of E2 and Ml for the cascade transition from the second 2 level.

This value of 6 can also be obtained from the magnetic spectrometer measurements of the

K-conversion co-efficient and the K/L ratio. The value of <5 can then be compared with the

value expected from the theory by Davydov and Fillippov.

The value of & and the ratio of the crossover-to-cascade for the second 2 level

obtained from our measurements would give the ratio of the reduced transition probability

for this level. This ratio can then be compared with the theoretically expected value from

* The alphanumeric designation refers to the NBS Program Structure (see Appendix II).

46
the various models.

From the final proposed decay scheme one can obtain the log ft. values (measures of

decay probabilities) for the various beta or electron conversion transitions. Also the

multipolarities of the various gamma rays could be obtained from conversion coefficient

measurements, and these would enable suitable spin and parity assignments to be made to

the various levels of the nucleus.

Results and Implications to Date

The decay of a number of nuclei such as "m , 103

Ru,

110m

Ag,

124

Sb,

131

Ba,

131

I,

133 13i+ 1141+ _ 144- 160,. 182„ 192 T , ., n

. , , . . . . , Ba, Cs, Ce, Pr, Dy, Ta, Ir, and other nuclei have been investigated

during the last six years of the project. For these investigations, a single crystal

scintillation spectrometer, a slow-fast coincidence setup, a modified sum-coincidence

spectrometer, and a sum-peak coincidence spectrometer have been utilized. The detectors

employed were two pairs of Harshaw's integral line assemblies containing 2" x 2" and

3" x 3" Nal(Tl) crystals having good energy resolutions. Thin Nal(Tl) crystals were also

used. Recently a Ge(Li) detector has been used for our investigations. The energies,

relative intensities and coincidence relations of various gamma rays emitted in the decay

of the nuclei under study were carefully measured. In general, wherever very weak gamma

rays or multiple gamma ray cascades were involved the modified sum-coincidence and sum-peak

coincidence spectrometers have been found very useful, because in the former the degraded

photons are not registered and in the latter the coincidence detection efficiency is very

high, especially when used in 3tt or 4tt geometries. In addition, gamma-gamma angular correlation studies have been made using the fast-slow coincidence setup. In some cases , the

sum-peak coincidence spectrometer has been utilized with advantage for this purpose.

Internal conversion coefficient measurements have also been made in a limited number of

transitions in some of the nuclei.

From our measurements , it has been possible to decide about the existence , intensity

,

and position of some of the low intensity gamma rays in some of the nuclei. The value of

& obtained in some cases have been compared with the values obtained from suitable nuclear

models. Interesting results bearing upon the applicability of such models have been

obtained

.

47
From the cross over-to-cascade ratios and the measured 5 values , the reduced transition probabilities have been obtained. These results, when compared with single particle

estimates , have yielded information about the nature of some of the levels

.

The multipolarities of a large number of gamma rays have been determined from our

measures 6 values and conversion coefficients (either measured or taken from literature).

This has enabled us to assign spin and parity to various levels of the above mentioned

nuclei. In some cases, the measured level structures were compared with the level

structures predicted by some nuclear models.

In addition to the above studies , theoretical neutron inelastic scattering cross115 127 197 section calculations have been made for a few levels in In , I , and Au using the

Hauser Feshbach method and a suitable optical model potential. The results have been compared with the measured level excitation cross-sections. Spin-parity assignments have been

made to these levels on the basis of these comparisons.

c c The data on Fe (p, p'y) reaction taken at Bartol Research Foundation, Swarthmore,

Pennsylvania, were analyzed. The experimental cross-sections of the various levels and

r c the angular distribution of the various gamma rays in Fe were obtained from this analysis.

Theoretical calculations for the level cross- sections and the angular distributions were

made using Moldauer's theory and a suitable optical model potential. Theoretical results

when compared with experimental results yielded spin assignments to a number of levels

r r of Fe excited in this reaction.

With the recently acquired Ge(Li) detector and a transistorized multi-channel

analyzer, it has been possible to measure energies of gamma rays emitted in the decay of

131 . . I to a precision of . 1 to . 2 % . We have been able to measure also the intensities

of gamma rays with much greater precision than hitherto possible.

The NBS/SFCP (PL 4-80) has provided research facilities to train many students in the

field of nuclear physics, and enabled us to provide some new information in the field of

nuclear physics.

The NBS monitor points out that nuclear decay scheme information is becoming

increasingly important to such fields as nuclear medicine, environmental protection, clean

nuclear energy as well as to basic science.

U8
List of Publications that Resulted from the Project

1. P. N. Trehan and N. C. Singhal, "Cross-section Measurements of (p, p'y) radiations from

Ni-62," Nucl. Phys. Symp. 9_, 342 (1965).

2. N. C. Singhal and P. N. Trehan, "Spin assignment for 268-keV Level of Au-197,"

Ind. J. of Pure and Applied Phys. 3_> 36 (1965).

3. P. C. Mangal and S. P. Sud, "Decay of Ba-133," Proc. Nuc. Phys. Symp. 9_, 287 (1965).

4. S. P. Sood and P. C. Mangal, "Decay of Ag-llOm," Proc. Nuc. Phys. Symp. 10, 234 (1966).

5. P. N. Trehan, N. C. Singhal, and P. C. Mangal, "States in Fe-56 Excited by the (p,p'y)

Reaction," Proc. Nucl. Phys. Symp. 10, 98 (1966).

6. C. M. Vasudev, K. K. Suri, and P. N. Trehan, "Spin Assignment to Some Levels of 1-127,"

Ind. J. of Pure and Applied Phys. 5_, 182 (1967).

7. P. C. Mangal, S. P. Sud, and P. N. Trehan, "Decay of Tantalum-182 ," Current Science, 36,

224 (1967).

8. P. C. Mangal and P. N. Trehan, "Gamma-gamma angular Correlation in W-182," Current

Science, 36, 337 (1967).

9. P. N. Trehan, P. C. Mangal, and D. M. Van Patter, "Angular Distribution of Fe-56

(p, p'y) Radiations," contributed paper to the International Conference on Nuclear

Structure held in Tokyo, Sept. 1967, J. Phys. Soc. , Japan, Suppl. 24_, 670 (1968).

10. S. P. Sud, P. C. Mangal, and P. N. 'Trehan, "Decay of Cd-115m and Ta-182," contributed

paper to International Conference on Nuclear Structure, Tokyo, Sept. 1967, J. Phys.

Soc, Japan, Suppl. 24, 663 (1968).

11. P. C. Mangal, S. P. Sud, and P. N. Trehan, "Sum-coincidence Spectrometry and the Study

of Weak Cascading Gamma Rays," Ind. J. of Pure and Applied Phys. 5_, 596 (1967).

12. C. M. Vasudev, K. K. Suri, N. C. Singhal, and P. N. Trehan, "Spin Assignment to Certain

Levels of In-115m," Ind. J. of Pure and Applied Phys. 6_, 50 (1968).

13. P. C. Mangal and P. N. Trehan, "A Note on 220 keV Gamma Ray Transition in Ba-133,"

Ind. J. of Phys. 41, 938 (1967).

14. P. C. Mangal and P. N. Trehan, "The Decay of Ce-144," J. Phys. Soc, Japan, 27, 1

(1969).

15. S. P. Sud, P. C. Mangal, and P. N. Trehan, "The Gamma-gamma Angular Correlation

Studies of Cascades of Cs-133 With Sum Peak Coincidence Spectrometer," Ind. J. of Phys.

(March 1968).

49
16. P. C. Mangal, S. P. Sud, Parveen Bawa, and P. N. Trehan, "Gamma-gamma Angular Correla1 31 tion in Cs," Aust. J. Phys. 23_, 79 (1970).

17. S. P. Sud, P. C. Mangal, and P. N. Trehan, "Gamma-gamma angular Correlation in 110Cd,"

Aust. J. Phys. 23_, 87 (1970).

18. S. P. Sud, B. K. Arora, and P. N. Trehan, "The K-shell Internal Conversion Coefficient

i 03

of the 53 keV Gamma Ray of Rh, " Ind. J. of Pure and Applied Phys. 7_, 441 (1969).

19. S. P. Sud, K. K. Suri, and P. N. Trehan, "The Decay of u Ru," J. Phys. Soc. , Japan,

_28, 1387 (1970).

1 24

20. S. P. Sud and P. N. Trehan, "The Decay of Sb," J. Phys. Soc, Japan, 29, 1387

(1970).

21. K. K. Suri, P. C. Nangal, and P. N. Trehan, "The Sum-peak Coincidence Spectra in Case

1 99 of Ir," Ind. J. of Pure and Appld. Phys. 8_, 394 (1970).

22. S. P. Sud and P. N. Trehan, "The Decay of Cs-134," J. Phys. Soc, Japan, 39, 919

(1971).

23. S. S. Bhati, et al, "Gamma-gamma Directional Correlation in Tc-99," accepted for

publication in J . Phys . Soc . , Japan

.

24. N. Singh, S.S. Bhati, R. L. Dhingra, P. C. Mangal, and P. N. Trehan, "Gamma-gamma

147 Directional Correlation in Pm, " contributed paper, International Conference on

Nuclear Moments and Nuclear Structure, Sept. 4-8, 1972, Osaka, J. Phys. Soc, Japan,

Suppl. (1973).

25. P. C. Mangal, "Investigations on the Decay of Some Radio-active Nuclei in the Medium

Weight Region," Ph.D. thesis, Panjab Univ., Chandigarh (1968).

26. S. P. Sud, "Measurements of Some Nuclear Parameters in the Decay of Certain Medium

Weight Nuclei," Ph.D. thesis, Panjab Univ., Chandigarh (1969).

27. K. K. Suri, "Studies of Energy States of Some Nuclei," Ph.D. thesis, Panjab Univ.,

Chandigarh (1970).

50
A. 5.* STANDARD REFERENCE DATA

Project Title : OPTICAL SPECTRA OF SIMPLE MOLECULES

Principal Investigators : Professors Putcha Venkateswarlu

Professor D. Ramachandra Rao

Institution : Indian Institute of Technology , Kanpur

NBS Monitor : Dr. Arnold Bass

NBS Institute or Center and Division : Institute for Materials Research

Physical Chemistry Division

Summary Description of Project Goals

An attempt will be made to measure the spectra of excited halogens and mixed halogens

trapped in argon matrix and to understand the effect of crystal fields. Single crystals of

- - - - 2+ alkali halides and nitrates will be grown with impurities like OH , , CN , N0„ and VO

and their optical spectra will be studied to understand the solid state effects on the

energy levels of these ions.

Sealed tube techniques and microwave excitation will be utilized in search of new free

radicals formed by the combination of the elements in group VI. High resolution spectra of

such molecules will be studied in order to obtain spin orbit coupling strengths and the

order of electronic configurations. Isotopically enriched samples will be used.

Emission spectra of iodine, bromine and chlorine will be recorded in the near infrared

and visible regions in order to study the band systems of these molecules and their ions.

These systems will also be looked into under high resolution. Attempts will be made to

obtain iodine molecular lasers in the predicted regions of 4400-4000 and 3500-3000A. During

the experiments on the emission spectra of halogens in the near infrared, attempts will be

made to obtain Easing action in this region also.

A study of thermal luminescence of I„, Br„ and Cl„ in presence of argon will be taken

3 3 upc to try-> to understand the relaxation mechanism in the tt + and tt.. states as well as o u 1 u

the formulation of these states. Further a study of I„ absorption at different temperatures

up to 1400°C will be attempted at high resolution together with juxtaposed emission spectra

in an effort to understand the correlation of absorption and emission in this region.

The NBS monitor states that from his viewpoint the Indian work is related to activities

in the Physical Chemistry Division that are concerned with problems of molecular structure

" The alphanumeric designation refers to the NBS Program Structure (see Appendix II).

51
and energy transfer in excited molecular states. These data are important for understanding

relaxation processes and chemical kinetics of halogen-containing species.

Results and Implications to Date

The necessary vacuum systems have been fabricated for the excitation of halogens. The

vacuum systems that are constructed can simultaneously be used for possible laser action by

employing appropriate mirror.

Work has started on L. In our preliminary experiments, in certain types of electric

discharge through iodine vapor, a number of main bands are observed in the region between

6700-9000 A . The spectra also show a large number of weak bands slightly diffuse. Some

of these bands appear to be the counter parts of the absorption band system already recorded

in literature. More intense investigation in this region of spectrum has been undertaken.

Spectra have been recorded under the following three conditions of discharge:

1. 9000V, DC discharge through iodine vapor

2. Microwave discharge (2450MHz) through iodine vapor in the same condition as above.

3. 12000 AC transformer discharge through iodine vapor

Results so far obtained indicate that the first two types of discharge give relatively

large number of atomic lines of iodine and are, therefore, not suitable for the production

of molecule bands. The third method of excitation has given a good number of fairly sharp

bands in the region between 54-00 and 8900 A. The spectra have been photographed on 1.4

meter Jarrell Ash f/6.3 spectrograph.

The spectrum produced by the AC discharge has been measured and the wave lengths of

the bands recorded. The absorption spectrum of the iodine vapor in the above discharge

tube has also been mapped employing a tungsten filament lamp as the continuous source.

Most of the bands obtained in absorption seem to be identical with the bands in emission.

Analysis of the bands is in progress.

Similar work on bromine and chlorine is about to start.

The spectra of N Se and N Se molecular species have been excited in microwave

discharge (2450MHZ) and photographed in the third order of a 3.4 meter Jarrell Ash spectrograph with a 30000 lines /inch grating. The analysis of the spectrum gives the following

molecular constants for the two brand systems studied:

52
2 2 ^3

/ 3, System, v

2

' 7

Molecular Constant 15N

78Se

(cm~^)

ti W

e

1!

929.68

W

e

it

V e 5.41

B

1 0.5061

B

2

ii

0.4820

B

3

ii

0.4785

B

4

ii

0.4760

B

5 0.4716

D

ite

5. 8 5x10" 7

W

1e 683.36

W

1

e e 42.39

B 1

o 0.3955

B

1

1 0.4020

= 23901.50 cm

1 e

15N80Se

(cnr-L)

927.80

5.39

0.5039

0.4806

0.4765

0.4726

0.4672

6.00x10

7

681.98

42.20

0.3938

0.3985

53
2 2 % - X % s

/

2 /

2

Molecular Constants

15

N

78

Se

(cnr-l-)

ii W

e 932.44

n ti W

e

11

V e 5.47

B

3

ii

0.4774

B

4

ii

0.4746

B

5 0.4707

D

iie

ii

0.5xl0~ 6

W

e 635.01

B 1o 0.3900

D

1e

0.5x10" 6

> = 24357.12 cm

1 e

15N

80

Se

(cm-1 )

930.52

5.45

0.4766

0.4725

4625

5x10"

6

633 73

0. 3885

0. 5x10"

6

List of Publications that Resulted from the Project

The project has only recently been undertaken and no substantial publications have

emerged so far.

54
A. 6." STANDARD REFERENCE MATERIALS

Project Title : PREPARATION OF STANDARD REFERENCE MATERIALS OF FERRO-ALLOYS

Principal Investigator : Professor V.A. Altekar

Associate Investigator : Dr. H. P. Bhattacharya

Institution : National Metallurgical Laboratory, Jamshedpur

NBS Monitor : Dr. R. E. Michaelis

NBS Institute or Center and Division : Institute for Materials Research

Office of Standard Reference Materials

Summary Description of Project Goals

This project involves the preparation, homogeneity testing, and analysis of three

ferro-alloys for use as NBS Standard Reference Materials in the following order of priority:

1. High-carbon Ferromanganese

,

2. Low-carbon Ferromanganese, and

3

.

Ferrotitanium

The crushing, grinding, mixing and sampling operations on 1/2 to 1 ton lots of the materials

will be undertaken initially, followed by chemical analyses of various sieve fractions to

establish the homogeneity. The ferro-alloys should conform to ASTM specifications A99

Grade A, A99 Grade A (low carbon), and 324 Grade B respectively.

The NBS distributes standard reference materials including those of ferroalloys used

by the steel industry throughout the world for the control of raw materials . Any help in

the preparation of these critical materials is clearly welcomed by NBS. From the point of

view of National Metallurgical Laboratory in India, the participation in this demanding

work increases the self confidence and credibility of NML in supplying these materials to

indigenous industry, as required by such industry.

Results and Implications to Date

The NBS monitor states that from his viewpoint the Indian work on the preparation,

testing, and certification of important ferroalloys has been performed in an outstanding

manner . NBS currently is involved in the preparation of two additional ferroalloys

,

specifically regular and high purity grade 75% silicon. This work also has international

ramifications in that the Bundesanstalt fur Materialprufung (BAM) in Germany is cooperating

" The alphanumeric designation refers to the NBS Program Structure (see Appendix II).

55
with NBS on this program. It has now been a number of years since NBS has had ferromanganese and ferrotitanium materials available, and therefore, the India project on these

ferroalloys highly complement and support the NBS program for maintaining a continuous

supply of important steelmaking alloys.

High carbon ferro-manganese

A suitable sample of high carbon ferro-manganese, fairly within the ASTM specifications

was received from M/s. Ferro Alloy Corporation Ltd. , India and one ton of the raw material

was thereafter obtained from this firm. Systematic studies on various sieve fractions of

a representative sample taken from the bulk lot of one ton showed that -60 + 100 BSS mesh

size would be most suitable for preparation of this category of standard sample conforming

to the suggested ASTM specifications. The bulk sample of 1000 kg was divided into two lots

and for each lot crushing, grinding, and homogenizing operations were carried out separately

in different batches and a total of 280 kg of standard sample was finally prepared. __

A99 Grade A(High C) Analysis of

Specification Element NML SRM

78.00% Min Mn 80.9%

0.35% Max P 0.183%

0.05% Max S Trace

1.20% Max Si 1.14%

7.50% Max C 6.77%

Low carbon ferro-manganese

Out of the two samples of low carbon ferro-manganese, the one received from M/s. Electro

Metallurgical Works , Bombay , was found to be of proper grade . An order was , therefore

,

placed for a supply of 500 kg of the material and against this only 380 kg of raw material

was received. Systematic crushing, grinding, and homogenizing operations on the 380 kg

of the material were carried out in different batches and 117 kg of the fraction of -60 +

100 BSS mesh size was finally obtained, an analysis of which is given below:

ASTM

A99 Grade A(Low C) Analysis of

Specification Element NML SRM

85 - 90 % Mn 85.6%

0.07 - 0.5% C 0.12%

2 - 00% Max Si 1.73%

0.20% Max P 0.118%

0.20% Max S Trace

56
Ferro-titanium

Procurement of ferro-titanium conforming to the standard specifications took the longest

time. It was indeed difficult to obtain 500 kg of the material conforming to our specifications made in one melt as per direction. Ultimately, after a good number of experimental

trials by the producers , a 500 kg lot of the raw material conforming to the specifications

was received from M/s. Indian Thermit Corporation Ltd. , Kanpur. The sieve fraction selected

was -60 + 100 BSS mesh size. Crushing, grinding, and homogenizing operations were carried

out in different batches. The final sample after homogenizing weighed 175 kg. The analytical data of the final sample are shown below: __

324 Grade B Analysis of

Specification Element NML SRM

20 - 27% Ti 24.98%

5.0% Max Si 2.31%

6.0% Max Al 5.64%

0.1% Max C 0.048%

It is hoped that these series of experiments which the NML has undertaken will be fruitful in scientific activities of the NBS and will provide a great help to the ferro-alloy

industries in rapid and accurate analyses of the raw materials and finished products in both

countries. A suitable portion of the high carbon ferro manganese will be immediately sent

to NBS for confirmative analytical tests and homogeneity appraisal. Plans will then be

made how to handle the other SRM's.

List of Publications that Resulted from the Project

This project has only recently been executed. When the NBS results on the SRM's are

available a literature publication may become desirable. The Journal of Research of the

National Bureau of Standards would be a good medium.

57
A. 6." STANDARD REFERENCE MATERIALS

Project Title : GLASS AND CERAMIC CHEMICAL COMPOSITION - SRM PROGRAM

Principal Investigator : Dr. S. Kumar

Institution : Central Glass and Ceramic Research Institute, Calcutta

NBS Monitor : Dr. Oscar Menis

NBS Institute or Center and Division : Institute for Materials Research

Analytical Chemistry Division

Summary Description of Project Goals

The project was to involve complete analyses of glass and ceramic materials as part of

the standard reference materials (SRM) program. It also was to include the development

and standardization of analytical methods for the determination of constituents for which

existing analytical methods cannot be satisfactorily applied.

Results and Implications to Date

Four SRM samples (two clays and two feldspars) were analyzed in triplicate by independent procedures after proper standardization. The constituents determined were SiO„, Al^O- 5

Ti0

2

, Fe

2 3

, CaO, MgO, P

2

, BaO, Na

20, and K20.

While analyzing SRM samples, it was found that analytical methods available in the

literature for certain constituents could not be satisfactorily applied to SRM samples , and

in such cases , investigations were carried out for the development of suitable methods or

modifications of existing ones . For example , the colorimetric determination of titanium

using hydrogen peroxide was not sufficiently sensitive in the range of 0.004-0.006% Ti0„.

Critical studies were carried out on the spectrophotometric determination of titanium using

chromotropic acid as the chromogenic reagent. The results of the investigation are being

prepared for publication.

The existing procedures for the colorimetric determination of residual silica by the

molybdenum blue method were also carefully studied and it was observed that the experimental

conditions were not properly defined to ensure reproducible results . In view of this

,

further investigations were carried out on this method and a satisfactory procedure was

developed uing ascorbic acid as the reducing agent.

" The alphanumeric designation refers to the NBS Program Structure (see Appendix II).

58
The present collaborative work provided the opportunity to check the precision of some

of the analytical methods that were developed or standardized in the Indian Laboratory and

to augment existing competence for such accurate analyses.

In a letter dated September 11, 1971 to Dr. Kumar, the monitor stated that "we are

pleased to report that, in general, your values are in very good agreement with provisional

values established for these four standards. As you know, feldspars and clays are very

complex materials which require considerable analytical skill. You and your associates are

to be complimented for the fine work which resulted from this cooperative program. " Thus

,

the NBS monitor states that from his viewpoint the Indian work provided valuable analytical

information on a number of complex SRM's which required considerable analytical skill and

experience

.

Two publications of this work at the Central Glass and Ceramic Research Institute are

being prepared. One of these being communicated to the Analyst , London is by B.C. Sinha

and S. Dasgupta, entitled "Spectrophotcmetric Determination of Silicon by the Heteropoly

Blue Method,"

List of Publications that Resulted from the Project

None to date.

59
A. 8.- MATERIALS MEASUREMENT METHODS AND STANDARDS

Project Title : LOW TEMPERATURE AND HIGH PRESSURE X-RAY INVESTIGATIONS OF PHASE TRANSIT! Oil .

:

Principal Investigator : Dr. K. V. Krishna Rao

Institution : Osmania University, Hyderabad

NBS Monitor : Dr. Stanley Block

NBS Institute or Center and Division : Institute for Materials Research

Inorganic Materials Division

Summary Description of Project Goals

In the past, X-ray investigations on the thermal behavior of a number of crystals

of rutile [1] and calcite [2, 3, 4, and 5] type structures have been undertaken. Studies

on the thermal expansion of many crystals belonging to the same crystal type are useful

in correlating the thermal expansion with other physical properties and parameters , such

as bond lengths and percentages of ionic character. Other interesting results obtained

are the negative coefficients of expansion along the unique axis in the case of FeF„, CrO„,

and RuO„. These studies have also been extended to single crystals [6] at low temperatures.

In a few cases the crystal structure has been refined to determine the B factors for

different atoms with a view to correlating the thermal expansion with the thermal vibrations [7]. The objectives of the present project are:

(1) to study the phase transitions, crystal structure, and the thermal

expansion of organic and inorganic compounds at low and high temperatures

;

(2) to study the thermal expansion and structure of organic and inorganic

crystals at room and low temperatures ," and

( 3

)

to study the phase transitions of organic and inorganic crystals under high

pressure

,

with special stress on rutile, calcite, and K

?S0U type compounds.

Results and Implications to Date

Although the official commencement of the project was September 23, 1971, there was

considerable delay in receiving the grant and the staff for the scheme was recruited only

in March 1972 when the actual work on the project commenced. The following is the progress

v The alphanumeric designation refers to the NBS Program Structure (see Appendix II).

Figures in square brackets indicate the publication reference at the end of this

project review.

60
made 30 far.

(a) Studies on Thermal Expansion

The lattice parameters of two ferrites , cobalt ferrite (CoFe

?Ou

) and cobaltzinc ferrite (Co„ ?Zn„ nFe„O

u

) have been determined in the temperature range 30 C

to 700 C to ascertain whether there are discontinuities in the variation of the

lattice parameters at the Curie temperature. It has been noticed that there is

no abnormality in the vicinity of the Curie temperature in either of the compounds. The coefficients of thermal expansion at different temperatures have been

evaluated using a graphical method.

(b) Determination of Crystal Structures

To determine the crystal structure of a - (phenyl sulphonyl )-chalcone,

C„-,H 0~S, whose space group has already been determined in this laboratory

[8], intensity data on 700 reflections have been collected by the photographic method from Weisseriberg photographs. The structure determination of this

substance is in progress.

A physiologically active compound bromohypophyllanthin C„„H 0Jr„

zM- zo / z is also taken up for investigation. The space group and the unit cell dimensions

have been determined from the rotation and Weiss enberg photographs . The intensity

data are being collected.

(c) High Pressure Studies

An MRC high-pressure high-temperature X-ray camera has been set up. The

first substance taken up for investigation is potassium nitrate, whose thermal

behavior has already been studied in this laboratory [7]. X-ray powder

photographs at atmospheric pressure and pressures of approximately 8 kb and 12 kb

have been recorded. The analysis of these photographs is in progress.

References

1. K. V. Krishna Rao, "Thermal Expansion of Crystals," Physics of the Solid State (Academic

Press, London and New York), 415-425 (1969).

2. K. V. Krishna Rao, S. V. Nagender Naidu, and K. S. N. Murthy, "Precision Lattice

Parameters and the Thermal Expansion of Calcite," J. Phys. Chem. Solids, 2S_, 245 (1968).

3. K. V. Krishna Rao and K. S. N. Murthy, "X-Ray Determination of the Thermal Expansion of

Magnesium Carbonate," Current Sci. , 38_, 162 (1969).

f-1
4. K. V. Krishna Rao and K. S. N. Murthy, "Thermal Expansion of Manganese Carbonate,"

J. Materials Science, 5_, 82 (1970).

5. K. V. Krishna Rao and K. S. N. Murthy, "Precision Lattice Parameters and the Thermal

Expansion of Sodium Nitrate," J. Phys. Chem. Solids, 31, 887 (1970).

6. K. V. Krishna Rao, P. Venkateswara Rao, and K. S. N. Murthy, "An Experimental Arrangement for Determining the Coefficients of Thermal Expansion of Crystals of Lower

Symmetry," Ind. J. Pure and Appl. Phys., 1, 138 (1969).

7. K. S. N. Murthy, "X-Ray Studies on Calcite Type Compounds," Ph.D. thesis, Osmania

University (1971).

8. P. Venkateswara Rao and K. S. N. Murthy, "Crystal Data on a-(phenyl sulphonyl )-chalcone,

Current Sci. , 36, 541 (1967).

List of Publications that Resulted from the Project

Two publications are under preparation.

62
A. 8.» MATERIALS MEASUREMENT METHODS AND STANDARDS

Project Title : CATALYTIC HIGH PRESSURE HYDROGEN TRANSFER REACTIONS

Principal Investigators : Dr. C. N. Pillai

Dr. M. Satyanarayana

Institution : Indian Institute of Technology, Madras

NBS Monitor : Dr. Ralph Klein

NBS Institute or Center and Division : Institute for Materials Research

Physical Chemistry Division

Summary Description of Project Goals

The objective of the work is to study the catalytic hydrogenation of aromatic compounds under pressure by hydrogen transfer from suitable hvdrogen donors . The work

will involve the development of catalysts , a study of reaction mechanisms , the development

of the reaction as a synthetic tool in organic chemistry, and a further detailed study of

suitable reactions from the technological point of view.

Results and Implications to Date

The project was activated only very recently; results are therefore as yet

unavailable

.

- The alphanumeric designation refers to the NBS Program Structure (see Appendix II)

63
A. 8." MATERIALS MEASUREMENT METHODS AND STANDARDS

Project Title : STUDY OF TRANSITION METAL OXIDES WITH SPECIAL REFERENCE TO THEIR CATALYTIC

PROPERTIES

Principal Investigators : Professor M.V.C. Sastri

Professor V. Srinivasan

Institution : Indian Institute of Technology, Madras

NBS Monitor : Dr. Ralph Klein

NBS Institute or Center and Division : Institute for Materials Research

Physical Chemistry Division

Summary Description of Project Goals

In the project it is envisaged to carry out a comprehensive investigation of the

preparation, solid state properties, and catalytic behavior of binary and ternary oxides

of a wide range of transition metals.

The NBS monitor states that because of the extensive work of the NBS Surface Chemistry

Section on adsorption , surface migration , surface reactions , and surface energies , the

interests of NBS have been very close to catalysis. The Indian work embodied in this

project is an extension of the work on surfaces, bridging the effort of NBS with industrial

applications . Since NBS has become more interested and involved with catalysis , the work

at IIT Madras is a natural complement of the clean surface work at NBS.

Results and Implications to Date

The work carried out under this project since its commencement in September 1970 to

date is summarized below in two parts: I. Preparation and solid state chemistry of the

complex oxides and II. Catalytic reaction studies thereon.

I. Preparation and solid state chemistry of complex oxides

(a) Mixed oxides of V and Zr experiments with the "precursor" method:

Two general methods are available for the preparation of complex (ternary) metal

oxides: (1) Solid state reactions between the respective oxides of the metals or

between their carbonates and oxides; and (2) The so-called "precursor" method [1]

involving essentially heating a complex compound of easily decomposable anions , such as

carbonates, oxalates and formates of the metal ions concerned; eg., Ba /~Ti0 (C„0

4

) 2 J

and Tl U0„ (H COO).,. The former method generally requires prolonged heating at rather

ij= The alphanumeric designation refers to the NBS Program Structure (see Appendix II).

Figures in square brackets indicate the publication reference at the end of this project

review

.

m
high temperatures (900 to 1500 C). The difficulties inherent in the control of

experimental parameters under such conditions are reflected in uncertainties in the

purity, homogeneity, and stoichiometric reproducibility of the products. The precursor

method, on the other hand, requires less exacting conditions and consequently has

greater promise of yielding products of desired composition and homogeneity. It was

therefore considered worthwhile to explore the possibilities and potentialities of

the precursor method for the preparation of the complex oxides of transition metals as

one of the important subsidiary goals of the project. During the period under review

the method was successfully employed for the preparation of complex oxides of vanadium

and zirconium from oxalate-precursors of the compositions

M

3 /fV0 2 (C2 4

) 2 J .6H

2 and M /f V0 (C2 4

) 2 J .n H

2 where M = Ba (II) or Sr (II). The thermal behavior of these compounds were studied by

the Differential Thermal Analysis and the Thermogravimetric methods. Mixed metal

oxides obtained as final products of decomposition were characterized by x-ray diffraction, magnetic susceptibility and electrical conductivity measurements. It was found

that decomposition in air resulted in pentavalent vanadium oxides, BaJ 0. , Ba V„0

7 and

-2

Sr V

7

, while decomposition in flowing nitrogen or in vacuum (ca.10 Torr) yielded

mixed tetravalent and/or trivalent vanadium (III) oxides. Perovskite type BaVO-,

obtained by the thermal decomposition of the corresponding complex oxalate in oxygenfree nitrogen atmosphere has a 4-H-polytypic structure in contrast with those of other

alkaline earth metal vanadates (IV), CaVO^ and SrVO^ which crystallize in a regular

perovskite structure [2]. The corresponding strontium compound nrepared bv similar

method was found to possess an anion deficient pervoskite structure, SrV0„ ?[-.

Perovskite type zirconates, AZr0„, (A = Ca, Sr, Ba, and Pb) have also been prepared

by the precursor method. Textraoxalato zirconates (IV) of the general composition

A„ £~ Zr (C„0

U

) U J .xH„0 were employed as the precursors. ZrO- in cubic form has been

obtained by a similar method from the corresponding ammonium compound.

In an attempt to prepare lower vanadium oxides , the thermal decomposition of

VOCJD^.ZH and (NH ) /~V0 (CJD^ J . 3H have been carried out under low pressure

_2

(ca.10 Torr) conditions. Both the compounds yxeld V„0~ as the final product.

65
In an attempt to prepare lower vanadium oxides , the thermal decomposition of

VOC

2 4 .2H2 and (NH^ /^VO (C

2 4

) 2 J .3H

2 have been carried out under low pressure

_2

(ca.10 Torr) conditions. Both the compounds yield V„0., as the final product.

The thermal decomposition of NFLVO.-. and the reduction of V

9 r in flowing hydrogen

atmosphere has been investigated by DTA to see if V„0~ and VCL were formed. NH V0„

decomposes endothermally around 200-210 C to yield an ammonium vanadium "bronze"

(NH ) V . The latter undergoes further reduction exothermally around 480° to yield

V 2°3-

In view of the importance of divalent transition metal vanadates (V) as catalyst

materials , a comprehensive study of both solid state chemistry and catalytic aspects

of such vanadates has been undertaken. The preparation, dehydration, and transformation [3] of Co(V0„)„. 2H„0 have been studied using DTA, infrared spectroscopy (IR),

and X-ray diffraction (XRD) methods.

(b) Ferrites

:

Ferrites , AFe„0

u

, with spinel structure, are of technical importance in view of

their ferrimagnetic [4] and catalytic [5] properties. The corresponding chromites

are also gaining importance because of their useful catalytic and ceramic properties

[6]. With a view to understanding the mechanism and the factors controlling the

formation of such compounds , the formation of ZnFe~0

u and NiCr„0u from the constituent

oxides has been studied. It is found that the lowering of oxygen pressure in the

ambient atmosphere favors ferrite formation while oxygen pressure has no effect on

chromite formation. Both the reactions follow a mechanism involving diffusion of

cations

.

(c) Mixes oxides of manganese and molybdenum:

Transition metal oxides featuring molybdenum have come into considerable

prominence as catalyst materials for a variety of reactions , such as oxidation , dehydration, and dehydrogenation of organic compounds. Since the catalytic and solid

state properties are generally related, a detailed study of complex oxides found in

the system Mn-Mo-0 was undertaken. Three important stoichiometric compositions are

known in the system: MnMoO , Mn MO , and Mn Mo~0 . MnMoO^ can be obtained by interaction of either MnC0

3 and MoO, or Mn0„ and MnOq

. Studies carried out by TGA and

r.r
effluent gas analysis (EGA) methods , reveal that the decomposition of MnCCL precedes

the formation of MnMoCl. The kinetic rate data for the reactions between MnCCL-MoO...

and MnCL-MoCL have been analyzed on the basis of various rate equations for solid state

reactions. It has been found that the former reaction is best described by the KrogerZiegler model, while the latter follows Jander's model. The DTA study of the reactions

in N atmosphere reveals that Mn 0, is the main reactive species in the reaction.

Marker studies of the reaction between pellets of MnCL and MoCL in air indicate that

2+ Mn xs the main diffusing species.

II. Studies on catalysis by mixed oxides

(a) Dehydrogenation of cyclohexane and cyclohexene on zinc molybdate catalysts:

Two samples of zinc molybdate catalysts were prepared, one by solid state

reaction between ZnO and MoO, and the other by co-precipitation as hydroxides from

zinc nitrate and ammonium paramolybdate . Both these catalysts promoted the dehydrogenation of cyclohexane and cyclohexene which could be associated with the Mo-0 n - -<-

bond character. The actual oxidation state of the cations under reaction conditions

was identified by electron spin resonance (ESR) spectroscopy and it was found that

a paramagnetic species (g = 1.9221) (probably Mo ) is the active species involved

in the dehydrogenation reaction.

(b) Decomposition of isopropyl alcohol on ZnMoCl and MnMoCL catalysts:

The decomposition of isopropyl alcohol on the molybdate catalysts obtained

by the solid state reaction has been studied with a view to correlating their

physico-chemical characteristics with catalytic activity. The catalysts promote

both dehydrogenation and dehydration of isoproply alcohol. This may be ascribed

to the almost equal values of apparent energies of activation (E ) for dehydrogenation (9.7 k cal.mole) and dehydration (13.1 k cal.mole). The values of E for y app

dehydration decreases with increasing MoO, content in the case of ZnMoCK, suggesting

thereby that MoCL is the active component for dehydration reactions.

On ZnMoO

u

, the dehydrogenation activity is increased in presence of hydrogen

but is unaffected by the presence of acetone. On the other hand, on MnMoO

u

, hydrogen

enhances both dehydrogenation and dehydration while acetone suppresses dehydrogenation. The energy gap values obtainted from the electrical conductivity measurements

under various atmospheres showed that the hydrogen pretreatment resulted in the

67
increase of the Fermi level. This would suggest that the enhanced dehydrogenation

in presence of hydrogen is related to the Fermi level as has been postulated by

Wolkenstein [ 8 ]

.

Micro-gravimetric measurements of adsorption of acetone and alcohol in MnMoOu indicate that the observed suppression of the dehydrogenation of isopropanol on it

in presence of acetone, is presumably due to occupation of the dehydrogenationsites by adsorbed acetone.

The products of decomposition of isopropanol on MnMoOu included appreciable

amounts of propane in addition to the main dehydration product, propylene. The

possibilities of propane- formation through hydrogenation of propylene by hydrogen

or by self-hydrogenation [9] or by hydrogen-transfer from the alcohol [10] were

experimentally examined and eliminated, leaving hydrogenolysis of the alcohol

itself as the only plausible mechanism for propane formation, as was found earlier

by Balandin [11] for the same reaction on Mo0~.

References

:

1. W. S. Clabaugh, E. M. Swiggard, and R. Gilchrist, J. Res. Natl. Bur. Standards,

56_, 289 (1956).

2. B. L. Chamberland and P.S. Danielson, J. Solid State Chem. , 3_, 243 (1971).

3. S. K. Bhattacharyya , G. S. De, and N. C. Datta, Thermal Analysis (Proceedings of the

Second International Conference on Thermal Analysis) 2_, 909, Eds. R. F. Schwenker, Jr.

and P.D. Gam, Academic Press, New York (1969).

4. A. B. Van Groenov, P. F. Bongers , and A. L. Stuyts, Materials Sci. Eng. , 3_, 317

(1968-69).

5. V. V. Popovskii, G. K. Boreskov, Z. Dzeventski, V. S. Muzykantov, and T.T. Shul'Meister

,

Kinetics and Catlysis, 12, 871 (1971).

6. G. C. Ulmer, "High Temperature Oxides," Part I, Ed. A. M. Alper, Academic Press,

New York (1970).

7. W. P. Doyle, G. McGuire, and G. M. Clark, J. Inorg. Nucl. Chem., 28_, 1185 (1966).

8. F. F. Wolkenstein, "The Electronic Theory of Catalysis on Semi-conductors," Pergamon

Press, Oxford , 66 (1963).

9. M. Taniewski and M. Otremba, J. Catalysis, 14, 201 (1968).
10. H. Niiyama and E. Echigoya, Bui. Chem. Soc. Japan, 45_ 938 (1972).

11. A. A. Balandin, G. V. Isagulyantes , N. P. Sokolava, and I.K. Zakhariycheva , Izv. Akad,

Nauk, SSSR, 1549 (1961).

List of Publications that Resulted from the Project

1. B. Viswanathan, J. Gopalakrishnan , V. Srinivasan, and M.V.C, Sastri, "Thermal

Decomposition of Ferrous and Manganous Oxalates in Vacuum," J. Thermal Analysis, 3_,

429 (1971).

2. M. V. C. Sastri, G. Aravamudan, J. Gopalakrishnan, and N. Ramadoss , "Perovskite Type

Zirconates from Thermal Decomposition of Tetra Oxalate- zirconates ," Presented at the

Dept. of Atomic Energy Symposium, Aligarh (Dec. 1972) , to be published.

69
B.I.* MATERIALS SCIENCE AND TECHNOLOGY

Project Title : INVESTIGATIONS IN THE CHEMICAL AND THERMODYNAMIC PROPERTIES OF REFRACTORY

MATERIALS INVOLVING OXIDES, NITRIDES, CARBIDES, ETC., AT HIGH TEMPERATURES

Principal Investigator : Dr. V. V. Dadape

Institution : National Chemical Research Laboratory, Poona, India

NBS Monitor : Dr. W. S. Horton

NBS Institute or Center and Division : Institute for Materials Research

Inorganic Materials Division

Summary Description of Project Goals

The vaporization of the oxides, nitrides and carbides of aluminum, magnesium,

chromium, titanium, zirconium, and other elements were to be studied using the Langmuir,

Knudsen , and other techniques ; the chemical interactions of these compounds at high temperatures were also to be studied.

The monitor states that at the time this project was initiated and during the period

of the grant, the work of transpiration paralleled similar work at NBS. It formed a

complement to the Knudsen vaporization of the Inorganic Materials Division.

Results and Implications to Date

The reaction of A£„0-/ . with aluminum monochloride has been investigated at high

temperatures (1325, 1380 and 14-25 K respectively) by a transpiration technique. The weight

loss data obtained at these temperatures and the chemical analysis indicate that the

equilibrium reaction:

Y M

2°3(c)

+ 3MC£

(g) = M2°(g)

+ MC*3(g)

+

:f M

(£)

holds good and the heat of reaction has been found to be -14.4 - 1.6 k cal. mole

Solid A&OCft and its thermal behavior

Crystalline A£0C£ prepared by the reaction of A£

?0„ with AllCl- in a sealed tube kept

at 593 K was found to decompose in the temperature range 723-773 K. The stability of the

solid was found to increase in a carrier gas (nitrogen) saturated with AlCl~ , y The

following table indicates the thermal stability of A&0CJI, v in an AlCl~, , atmosphere. y (c) 3(g)

" The alphanumeric designation refers to the NBS Program Structure (see Appendix II)

70
Temperature

in K

Flow rate of

nitrogen

mJl./min.

Percent

decompos ition

of AlOCl , x (c)

Remarks

673 40 20% ) No AlCl~, v

> 3(g)

723 45 60% ) was added to

773 40 Decomposed com- \ pletely

.

the carrier gas.

823, 873, 923

973

35

25

No decomposition

was observed. ]

80%

Carrier gas was saturated

with AlCl~, s .

1 3(g)

998 25 95%

1023 25 Decomposed corn- pletely.

The chemical analysis of the products indicates that the decomposition may be expressed

as follows

3A£0C£

(c) 3(g) 2 3(c)

Reaction of AlCl. s with MgO, N (g) ^ (c)

The reaction of aluminum monochloride with magnesium oxide was investigated between

1298 and 1465 K employing a flow method. The products of the reaction and the weight loss

measurements suggest that the equilibrium reaction was

4Mg0, & v + 3AlCl, » (c) (g)

The reaction yielded a third law heat, AH

MgA£ & o0,,, , + AlCl^, » + 3Mg, ,. 2 4(c) 3(g) &

(g)

29:- 21.85 - 0.84 k cal. mole which compared

favorably with the second law value of 24.03 - 2.49 k cal. mole . These values gave -

553.36 - 1.89 and - 551.18 - 3.55 k cal. mole , respectively, for the heat of formation

of magnesium aluminate from the elements. The heat of formation of MgAJ,„0

U(

. -. from the

oxides at 298 K was found to be 9.26 - 1.1

- 3.55 k cal. mole from the second law.

k cal. mole from the third law and - 7.

Reaction of AlCl, , with BeO, .. (g) (c)

The results of the studies of the reaction AlCl, >. with BeO, , at 1389 - 1492 K suggest

the following reaction:

4 BeO, v + AlCl, . + AlCl~, s (c) (g) 3(g)

about 10% AlCl~, J. 3(g)

Be0:Aln o , , + 2BeC£, , + BeC£ n/ v [AlCl, , contained

2 3(c) (g) 2(g) (,g)

71
Over the temperature range, the AH was found to be 103.56 - 10.29 k cal. mole . From

the recent experimental data and available thermal functions, the AEU for BeCsi/ -. was

found to be + 7.23 - 5.15 k cal. mole by second law and the corresponding third law

value was - 5.67 - 0.60 k cal. mole

Vapor pressure of nickel chloride (NiC2.„)

The vapor pressure of NiC5,„ was determined over a temperature range 1030 to 1116 K

employing a transpiration technique. The vapor pressure equation can be represented as

+ log P ^ = - Ihl7 7 - 3 ~ 322 - 65 b+ 9 .0603 - 0.3

atm. T The calculated heat of sublimation is 58.11 - 1.47 k cal. mole~ . The sublimation

temperature at 760 mm. pressure was found to be 1244.8 K.

Equilibrium reaction Ni(c) + NiC£

9 (g) = 2NiC£(g)

The above reaction was studied between 1278 and 1380 K using a flow method. The

AH was found to be 152.66 - 6.77 k cal. mole

-1

and the AS = 100.46 - 5.06 r

1329

_ _ r

1329

cal. deg. mol.

Yttrium oxychloride YOCil

Y0C£ was obtained by heating YCS> 6H at 450-475 K. It loses water and hydrochlorine

acid molecules at these temperatures forming Y0C£.

The decomposition study was carried out in an atmosphere of purified argon at temperatures upto 1593 K. The oxychloride was found to decompose as follows:

3Y0Cil(s) = Y

2 3 (s) + YC£3 (g)

After the experiments , the residue in the boat and the gaseous product condensed on a

cold finger were chemically and spectrograDhically analyzed for Y 0, and YC£ ^respectively.

The condensate showed the presence of YCi> only. At 1593 K Y0CS, decomposed completely

leaving only Y-0- in the boat.

The results of the dissociation experiments carried out between 1188 K and 1593 K are

given in the following table:

72
Experimental data on the decomposition of YOCft(s)

Temp. K P, 4 s Log P (atms)

1188

1288

1328

1373

1408

1468

1498

1573

1593

Reaction of NiCX, (g) with Ni(c)

9.3884 X io-4 -3.0274

1.2257 X io- 3 -2.9115

1.3730 X io3 -2.8625

1.5368 X

_3

10 -2.8142

1.7713 X io"

3 -2.7517

1.8479 X io" 3 -2.7333

2.4417 X io"

3 -2.6494

3.6090 X io"

3 -2.4426

3.7039 X io"

3 -2.4313

The equilibrium study of the reaction

Ni(c) + NiC^Cg) = 2NiC£(g)

was carried out between the temperatures 1243 K and 1396 K using the transpiration

technique. The heat of reaction AH at the mean temperature was found to be 87.9 - 4.9 r1320

k cal. mole and the entropy AS of the reaction was 50.2 - 3.7 e.u. The entropy r

1320

of NiCil(g) at 1320, calculated from this was 81.1 - 2 e.u. which compared satisfactorily with

that calculated from Brewer's model (77.1 e.u. at 1573 K).

Action of A£CS> (g) on Ni0(c)

The reaction was carried out between 1270 and 1448 K. By a careful consideration of the

gaseous products which condensed on the cold finger, the following two reactions are

considered

4NiO(c) + 2AlCl

3 (g) = NiAJ^O (c) + 3NiCJ>

2 (g) ...1

2Ni0(c) + 2A£Cii

3 (g) = 2A£OC2(g) + 2Ni«

2 (g) ...2

The overall reaction is given by:

6Ni0(c) + 4A£C.?-

3 (g) = NiA£ O^Cc) + 5NiC£

2 (g) + 2Ai>0C£(g)

The H is 201.2 k cal. mol

-1

and S is 138.9 e.u. r1359 r1359

Study of the reaction between AlTAg) and A£(£) by transpiration technique

The reaction A£F„(g) + 2A1(£) * 3A£F(g) was carried out in a platinum lined mullite tube

between 1295 and 1375 K. The furnace was 24" long and Kanthal wound and had two constant

temperature zones.

73
An E. Merck grade A&T? sample was employed. Its spectrographic analysis showed the

presence of Si, Fe, and Cu in traces. The aluminum used was in the wire form (BDH A.R.

grade). A£,F~ and M were kept in platinum and graphite boats respectively.

The aluminum wire was cut into small pieces and purified in a stream of dry, purified

argon gas at about 1273 - 1303 K. Thus volatile impurities (if any) were removed. Purified

argon gas saturated with A&F- vapor was passed over A8.(0. The amount of aluminum transported during the reaction was known by the loss in weight of the metal contained in the

graphite boat.

The third law values for the heat of reaction were obtained from AH or, n = T(-R?,nk -AFef)

298 p

where k = equilibrium pressure,

A Fef values were obtained from JANAF tables

,

T is absolute temperature in K.

Experiments were carried out at three temperatures and the corresponding third law

values for the heat of reaction are given in the following table:

Temperature AH _

_

in Third law

1295 52.65 k cal. mole" 1

1335 50.06 k cal. mole"

1375 51.25 k cal. mole

-1

W.P. Witt and R.F. Barrow (Trans. Faraday. Soc. 55, 730 1959) have reported a third law

value of 57.58 k cal. mole for the above reaction.

Reaction of NiC£„(g) with molten aluminum

The reaction between nickel dichloride and molten aluminum was studied at high temperatures by the transpiration method. Gaseous nickel dichloride was passed over molten aluminum

between 1298 and 1400 K. An examination of the products remaining in the boat indicated the

presence of nickel and aluminum metals. Aluminum trichloride was found condensed in the

receiver. In order to study the composition of exit gases, the gaseous products were

condensed on a cold finger made of silica. The substance collected on the cold finger was

scraped and analyzed chemically and spectrographically revealing the presence of nickel and

aluminum. Aluminum metal can be attributed to the dissociation of A£C2.(g). The nickel

metal formed by the disproportionation of NiC£(g) according to the equations:

74
2NiC£(g) = NiC£

2 (g) + Ni(c) ...1

3A£C£(g) = AilC^

3 (g) + 2A£(£) ...2

With the above products the following reaction stoichiometry can be written:

NiCJUCg) + Alii) = NiCHg) + A£C£(g) ...3

2NiC£

2 (g)+ 3A£(£) = 3A£C£(g) * NiC£(g) + Ni(c) ...4

2NiC£

2 (g)+ Ai(Z) = AiCi3 (g) + NiC£(g) + Ni(c) ...5

2NiC£

2 (g)+ 2A£(£) = A£C£3 (g) + A£C£(g) + 2Ni(c)...6

NiC£ (g) + 3A£(£) = NiA£ + 2A£C£(g) ...7

NiC£

2 (g) + 2A£(£) = 2A£C£(g) + Ni(c) ...8

With increase of temperature more and more nickel metal is formed thereby showing that

the reaction is endothermic and must occur with an increase in entropy. So reactions 5, 6,

7 , and 8 can be neglected

.

Out of the reactions 3 and 4, reaction 3 can be neglected on the basis that there is no

possibility of the formation of nickel metal. The experimental results obtained, when

fitted into the reaction 4, are showing some discrepancies between the values of calculated

and observed free energies.

Study of the reaction of A£C£

3 (g) with Mn-Ou (c)

An equilibrium study of the reaction AiCiAg) with Mn-CXCc) has been carried out between

the temperatures 1213 K - 1433 K, by the transpiration technique using argon as carrier gas.

Analysis of the products showed the following stoichiometry

Mn

3 4

(c) + 3.5 A£C£

3 (g) = 1/2 A£2 3 (c) + 2.5 A£0C£(g) + 3 MnC£

2 (g)

+ C£

2 (g)

Employing the heat content functions , the third law value calculated for the heat of

reaction is 210 - 3.14 k cal. mole" . From the least square fit for the graph of -log K

vs 1/T K a straight line having the slope 199.8 was obtained. This when converted to 298 K

using the c values yielded a second law value of 214.3 k cal. mole for AH . It can be

[seen that the two values agree well with one another.

The above values for the heat of reaction gave the heats of formation for A£0C£(g)

AH,- = -89.5 k cal. mole" and -91.2 k cal. mole" for second and third laws respectively.

r 298

They may be considered to be in good agreement with the reported value (-84 -5k cal. mole )

in view of the complicated nature of the reaction and the temperature dependent errors.

75
Reaction of A£C£

3 (g) with NiO(c)

Employing the flow technique the equilibrium reaction between AlCiAg) and NiO(c) was

studied at temperatures 1269-14-4-0 K. The reaction may be represented as follows:

6Ni0(c) + 4A£C£

3 (g) = NiAJ^O^c) + 5NiCS>2 (g) + 2Aa0Ci(g)

It yielded a second law heat AH„

qft = 203.67 - 5.04 k cal . mole . A value of -83.59-

2.5k cal. mole was obtained for the heat of formation of AdOC£(g) which is in good agreement with that (-84 -5k cal. mole )reported in the literature.

Reaction between La„0o and AlCl~

The thermodynamics of the following reaction:

6La

3 (c) + 11AJ,C£ (g) = 5LaC£ (c) + 7La0Cs>(c) llAlOCKg)

was investigated between 719 and 877 K. LaOCi was identified by X-ray analysis of the

residue after leaching LaCX.., with water. The formation of A«.0C£(g) was noted by the

presence of Al„0~. deposit (A2.0CJI dissociates into A£C£- and AfcJD-J on the cold finger.

The experimental data was used to calculate the heat of formation of A£0CX,(g) at 298 K and

a value for AH - 95.93 k cal. mole is obtained. Considering the complicated nature

of the reaction this value appears reasonable when compared to the reported value of

-84 - 5 k cal. mole

-1

.

List of Publications that Resulted from the Project

1. D. Bhogeswara Rao and V. V. Dadape, "Equilibrium Studies of the Reaction 2Al(l) +

A£Cii

3 (g) t 3A£C£(g)," J. Phys. Chem. 70, 1349 (1966).

2. D. Bhogeswara Rao and V. V. Dadape, "Reaction of MCl(g) with MgO(s)," J. Phys. Chem.

71, 537 (1967).

3. M. Atchayya and V. V. Dadape, "Oxygen Removal Capacities of Light Lanthanon Sesquisulfides and Vaporization of La„S_," J. Less Common Metals 13_, 559-562 (1967).

4. B. Seshagiri Rao and V. V. Dadape, "Sublimation Pressure of Nickel Dichloride and the

Study of the Reaction Ni(s) + NiC£ (g) + 2 NiCUg)," J. High Temperature Science.

76
B.I.* MATERIALS SCIENCE AND TECHNOLOGY

Project Title : PLATINUM GROUP METAL COMPLEXES, THEIR PREPARATION, STRUCTURE AND ROLE IN

HOMOGENEOUS CATALYSIS

Principal Investigator : Dr. M. M. Taqui Khan

Institution : Indian Institute of Technology, Madras

NBS Monitor : Dr. T. D. Coyle

NBS Institute or Center and Division : Institute for Materials Research

Inorganic Materials Division

Summary Description of Project Goals

This project is aimed at the preparation of new complexes of ruthenium, osmium, iridium,

rhodium, platinum and palladium with tertiary phosphine and arsines, polytertiary phosphines

and arsines, alkyl and aryl sulfides, and olefinic and hydrocarbon ligands. It is intended

to elucidate their structure and study their catalytic properties in the activation of small

molecules like molecular hydrogen, oxygen, and nitrogen. The Droject is aimed specifically

at the homogeneous hydrogenation of alkenes and alkynes catalyzed by platinum group metal

complexes

.

In regard to the relation to NBS programs, the monitor suggests that the project is of

significance since it treats the chemical reactivity of small molecules in the coordination

sphere of transition metal ions of catalytic significance. These processes are of interest

to NBS in connection with possible approaches to novel reference materials and also from

the viewpoint of metal-mediated organic transformations related to water quality problems.

Results and Implications to Date

The platinum metal group ions that have largely been investigated for their catalytic

activity in homogeneous hydrogenation include mostly the complexes of rhodium( I )

, iridium( I )

,

platinum(II) , and palladium(II) with a d configuration. In the course of the present

work, new complexes of ruthenium and osmium with ad or d configuration were prepared,

their structures were studied by the usual physicochemical techniques and their catalytic

efficiency in the homogeneous hydrogenation of alkenes investigated. The list of complexes

prepared is presented in Table I.

" The alphanumeric designation refers to the NBS Program Structure (see Appendix II)

77
TABLE I

Properties of Ruthenium and Osmium Complexes

Complex*4 Color Solubility"" Melting Point in °C

1. RuC£

2 (AsPh

3

) 3 brown very soluble

in benzene

210-211°

2. RuCS> (diphos)

? yellow soluble in

benzene-DMF

295-297°

3. RuCUSnCS>

3 )(PPh

3

) 2 brown soluble in

benzene

decomposes on heating

4. RuCH(SnC)l

3 )(AsPh3

) 2 yellow soluble in

benzene-DMF

-"-

5. RuCUSnClJCdiphos) yellow _!!_ ""-

6. RuC£

2 (HgC^)(PPh3

) 3 brown soluble in

benzene and

chloroform

-

7. RuC«,

2 (HgC«.)(AsPh ) 3 brown _!!_ ""-

8. RuC^

2 (AsPh3

) 3 (0

2

) brown _!t_

9. RuC£

2 (PmeFh

2

) 2 (AsPh'

3 )(0

2

) green _!!_ -"-

10. RuCX,

2 (PPr2Ph)

2 (AsPh

3 )(02

) green _l?_ -"-

11. RuC^

2 (PPh3

) 2 (AsPh

3

) (0

2

) green _ll_ -"-

12. RuHC4(AsMePh

2

) 3 C0

2

) yellow _lt_ -"-

13. RuHC£(AsPh

3

) 3 (0

2

) brown _ll_ -"-

14. RuC£ (HgCSl ) ( PMePh

2

) (.0 ) brown _II_ -"-

15. RuC£

2 (SrO3 )(AsPh3

) 3 (0

2

) brown _-H_ -"-

16. RuC£

2 (NO)(02 )(AsPh

3

) 2 brown _!!_ -"-

17. RuC^

2 (N

2 )(0

2 )(AsPh3

) 2 brown _It_ -"-

18. OsCJ^CAsPhu) pale yellow soluble in DMSO 218-220°(decomp)

19. fac-OsC^

3 (SbPh

3

) 3 green _IT_ 277-280° -"-

20. 0sC£ l4 (PPh

3

) 2 yellow _IT_ o -"- 238-240

21. 0sC8,

4 (PPr

2Ph)2 yellow _ir_ 225-226° -"-

* Ph = phenyl

(disphos.) = [(PPh„) CH -]

DMF - dimethyl formamide

DMSO = dimethyl sulfoxide

78
TABLE I (Continued)

22.

23.

24-.

25.

26.

Complex5

'1 Color Solubility-:* Melting Point in

OsC^,

4 (PPh

2Me)2 yellow soluble in DMSO 222-224° (decomp)

OsCs> 4 (SbPh

3

) 2 black _h_ 240-242° -"-

OsC«,(SnC£

3 )(CH

2 (PPh2

) 2) 2 yellow _!!_ decomposes on heating

OsCx,(SnC£) (diphos) yellow _!l_ _it_

OsC£(HgCX.) (diphos)

„

colorless _!!_ _!!_

Catalysis of the homogeneous hydrogenation of alkenes by ruthenium (II) complexes of

the type LgRuCAX (L=AsPh

3

, SbPlu , or 2/3 {l,2-bis(diphenylphosphino) ethane} = (diphos) ,

X = CtT or SnC£

3 ") and LgRuCJi (HgCz,) (entries 1-7, Table I) have been studied at 35° and

45 C and one atmosphere of hydrogen. In the case of L„RuC£X complexes, the active catalytic

species seem to be hydrides of the general formula, L~RuHX. Some of these hydrides like

(AsPh~)~RuHC£ have been very well characterized.

The catalytic activity of ruthenium(II) complexes is very much dependent on the

IT-acceptor character of the neutral ligand L and decreases in the order, PPh-> AsPh->

SbPh„> diphos. The catalytic effect is enhanced when X is a corrdinated SnC£ ~ group.

Complexes of the type L„RuC£ (HgCO are non-catalytic in the homogeneous hydrogenation of

alkenes

.

The enthalpy and entropy of activiation for the hydrogenation of cyclohexene

catalyzed by L.RuC&CSnCjl-) (L=PPh~, AsPh„) have been found to be 2.1 k cal. mol and -53e.u.

(L=PPh

3

) and 1.3. k cal. mol and -56e.u. (L=AsPh„), respectively. The high value of the

entropy of activation supports a polar transition state where molecular hydrogen is split

heterolytically into hydride ion and proton by the catalytic ruthenium( II ) species. The

rate of the hydrogenation reaction is much enhanced in the presence of a basic cosolvent

like ethanol, lending further support to the heterolytic fission of molecular hydrogen.

The catalysis by ruthenium(II) in the homogeneous hydrogenation of alkenes is different

Q from that by the d ions like iridium(I) and rhodium(I) in the fact that there is no change

" Ph = phenyl

(disphos.) = [(PPh

2

) CH

2-]2 fac = facial isomer

** DMF = dimethyl formamide

DMSO = dimethyl sulfoxide

79
in the oxidation state of ruthenium(II) during the catalytic process.

Ruthenium(II) complexes are also very reactive in the activation of molecular oxygen.

The complex RuC£„(AsPh~) ~ combines reversibly with molecular oxygen to form a 1:1 dioxygen

complex of the composition RuC&

9 (AsPh~)„(09

) (entry 8, Table I). Complex 8 is paramagnetic, m ,.,. = 2.90 B.M. , corresponding to two unpaired electrons. That the complex

reacts with sulfur dioxide to give a sulfato complex is shown by its infrared spectrum.

On reaction with molecular hydrogen a hydrido complex of the composition RuHCjKAsPh.-,) „ is

obtained. The displacement reaction of 8 by molecular hydrogen is reversible and the

dioxygen complex is reformed on passing molecular oxygen through the hydrido complex in

solution. In benzene solution, complex 8 catalyzes the oxidation of triphenylphosphine

(B)(7) (8) to phosphine oxide. Though rhodium(I) and platinum(O) catalyze the oxidation of

triphenylphosphine, complex 8 is the unique example in ruthenium chemistry that catalyzes

such oxidations.

Entries (9-17) in Table I represent other dioxygen complexes of ruthenium( II ) prepared

as an extension of the program on the activation of molecular oxygen. All the dioxygen

complexes mentioned in Table I have been characterized by the infrared peak in the region

850-900 cm" assigned to 0-0 stretch of the triangular Ru-0„ group. Some of the dioxygen

complexes have also been characterized by a band in the visible region around 6200 A,,

assigned to a possible tt -a electronic transition. Detailed calculations are being performed to confirm the above assignment.

Complexes 12 and 13 (Table I), exhibit peaks around 1960 cm assigned to the rutheniumhydride stretching frequency. These complexes are novel because of the presence of peaks

characteristic of coordinated dioxygen along with that of hydride. The coordinated dioxygen

in compounds 12, 13, and 15 (Table I) is stabilized to reduction to such an extent that it

is not reduced in the presence of strongly reducing hydride or SnCj, „ groups . Compound 16

(Table I) contains both coordinated dioxygen and nitric oxide as confirmed by the presence

of infrared frequencies characteristic of coordinated dioxygen and nitric oxide. Complex

16 reacts with anhydrous hydrazine in methanol to give complex 17 that has both coordinated

dioxygen and dinitrogen. The complex is the first example of a compound that has coordinated dioxygen and dinitrogen and offers great promise as a model for further work on a

possible oxidative route for the fixation of nitrogen.

80
Complexes 18-26 (Table I) represent some of the new osmium complexes that have been

synthesized and fully characterized. The work on the preparation of platinum group metal

complexes and their use in homogeneous catalysis is being continued with particular

emphasis on:

1. Testing the catalytic properties of complexes of osmium, entries 18-26 (Table I)

for homogeneous hydrogenation and oxidation.

2. Study of nitrogen fixation by an oxidative route and preparation of complexes

similar to that of 17.

3. Study of the catalytic properties of the platinum group metal complexes of polydentate phosphines such as: PhP(CH CH PCPhJ^; P(CH CH P(Ph )„; and

C„R (P(Ph„)CH CH„P(Ph„)

? as possible bi- functional catalysts in homogeneous hydrogenation.

References

1. J. A. Osborn, F. H. Jardine, J. F. Young, and G. Wilkinson, J. Chem. Soc. , (A),

1711 (1966).

2. L. Vaska and R.E. Rhodes, J.Am. Chem. Soc, £T7_, 4970 (1965).

3. H.A. Tayim and J. C. Bailar, Jr., J. Am. Chem. Soc, 89_, 4330 (1967).

4. R.D. Cramer, E. L. Jenner, R. N. Lindsey, and U.G. Stolberg, J. Am. Chem. Soc,

85, 1691 (1963).

5. M. M. Taqui Khan, R. K. Andal, and P.T. Manocharan, Chem. Comm. , 561 (1971).

6. B. R. James and F.T.T.Ng, Chem. Comm., 908 (1970).

7. B. R. James and E. Ochiai, Can. J. Chem., 49_, 976 (1971).

8. S. Otsuka, A. Nakamura, and Y. Tatsuno, J. Am. Chem. Soc, 91, 6994 (1969).

List of Publications that Resulted from the Project

1. M. M. Taqui Khan and R. K. Andal, Proc Dept. of Atomic Energy Symposium (India),

1, 253 (1970).

2. M. M. Taqui Khan, R. K. Andal, and P.T. Manoharan, Chem. Comm., 561 (1971).

3. M. M. Taqui Khan and R. K. Andal, Proc Dept. of Atomic Energy S

81
B.l.» MATERIALS SCIENCE AND TECHNOLOGY

Project Title : ELECTRICAL BEHAVIOR OF PURE AND DOPED OXIDES AND OTHER IONIC SOLIDS

Principal Investigator : Dr. E. C. Subbarao

Institution : Indian Institute of Technology, Kanpur

NBS Monitors : Dr. J. B. Wachtman, Jr.

Dr. H. S. Bennett

Dr. Robert S. Roth

NBS Institute or Center and Division : Institute for Materials Research

Inorganic Materials Division

Summary Description of Project Goals

ZrO

? and Th09

, doped with divalent and trivalent metal oxides , have become interesting

as solid electrolytes for fuel and galvanic cells , in oxygen gauges , in magnetohydrodynamic

devices, etc. Their use is primarily based on the high oxygen ion conductivity in these

materials. The present study aims at relating the defect structure of these doped oxides

to the conductivity behavior. The role of size, valence and amounts of the impurity ions

will be examined. Electrical conductivity of interest here includes ionic, electronic,

and hole conductivity and its variation with temperature, oxygen partial pressure and

frequency of measurement. The phase relations in the binary system Zr0

9 - Y 0, are

clarified, since this system includes materials of interest as refractories, solid electrolytes and in MHD.

The NBS monitor states that from his viewpoint the Indian work is of interest because

there is related work at NBS in several areas. First, the work on phase transformations

in Zr0

9 and phase equilibria of Zr0

9 complement work by Dr. R. S. Roth on phase equilibria

in the ZrC^-NbuOj- system. Second, measurements of electrical conductivity at high temperatures are of interest to Dr. H.P.R. Frederikse who is studying electrical conductivity in

high temperature electrode insulator materials. Third, defect calculations in the fluorite

structure parallel similar calculations made at NBS by Dr. A. D. Franklin. The Indian

program relates to on-going NBS programs in the sense of providing additional basic data on

the general types of behavior under study.

Results and Implications to Date

A. Studies on zirconia

Zirconia has a high melting point (about 2700°C) but its use as a refractory is limited

The alphanumeric designation refers- "to the NBS Program Structure ( see Appendix II

)

82
by the two solid state transformations it undergoes at 1170 C from monoclinic to tetragonal

and at 2370 C from tetragonal to cubic symmetries. Besides, zirconia - based materials are

serious candidates in solid electrolytes , fuel cells and MHD devices . Hence a detailed

understanding of the phase transformations and thermal behavior of zirconia is crucial.

These studies are summarized in the following four subsections:

(1) Axial Thermal Expansion of Zr0„ and Hf0„ in the Range Room Temperature to 1400 C.

The materials used were high purity Zr0„ (total metallic impurity 2000 ppm) from

Bhabha Atomic Research Center, Bombay and spectrographic grade (99.9%) Hf0„ from the

Wah Chang Corporation, USA. A Tern-Press Research high temperature furnace was used on

a General Electric XRD-6 diffractometer to record a number of reflections (ten to

twelve) in the range 20 <2^ <65 in air. Filtered CuK radiation and a scanning speed

of 0.2 or 0.4 per minute were employed. The position of the recorded peaks were

determined with an accuracy of ± 0.02 and the desired temperature was maintained

within ± 4°C.

The reflections studied in the case of monoclinic Zr0„ were 111, 111, 002, 020,

200, 112, 202, 022, 220,131 and those in the tetragonal phase were 101, 002, 110, 112,

200, 103, 211, 202. Using the d value equation for the monoclinic lattice and the

200 values, we solved all the possible combinations of the above mentioned reflections

by a least squares method to give 170 values for each of the lattice parameters of

monoclinic Zr0„ at each test temperature. The reflections 111, 111, 002, 020, 200, 021,

211, 022, 220, 202, 221, 131 for monoclinic Hf0„ were used and 344 values for each

parameter were calculated. The lattice parameters at room temperature along with

maximum deviations are listed in Table 1.

Table 1 Lattice parameters of Zr0

2 and Hf02 Phase Temperature

(°C) a(8)

b

(ft

(deg)

Monoclinic

Zr0

2 Room Temperature 5.1415+5 5.2056±5 5. 3128±5 99°18'±5'

Tetragonal

Zr0

2

1393 3.6526±15 5. 2928±27

Monoclinic Room Temperature 5.1093±5 5.1686±5 5. 2839±5 99°9'±5'

Hf0

2 1400 5.1747±5 5.1897±5 5.,3787±5 98°25'±5'

83
Lattice parameter values , unit cell volumes , cube roots of the volumes and their

percentage expansions at various temperatures , in the monoclinic and tetragonal phases of

ZrO„ and for the monoclinic phase of HfO„ were obtained. The values of the lattice parameters were fitted to an equation of a straight line in order to obtain the axial expansion

coefficients. These values are listed in Table 2.

Table 2

Expansion Coefficients of ZrO„ and HfO„

Phase Temperature a axis b axis c axis volume

(range) (°C) (x 10 ) (x 106 ) (x 106

) (x 10&)

Monoclinic R.T.-1040 10.31 1.35 14.68 26.85

Zr0

2 Tetragonal 1400-1150 11.61 16.08 38.37

Zr0

2 Monoclinic R.T.-1400 9.34 2.98 13.10 27.18

Hf0

2

There are three especially interesting features of the thermal expansion behavior

of Zr0

2 and HfO .

(i) There is a large extent of anisotropy of thermal expansion shown by the

fact that the length of the b axis of Zr0„ and Hf0„ stays essentially constant,

am and c increase, and B decreases. The anisotropy could be associated with -the

low symmetry and complex bonding with a considerable amount of covalent character.

(ii) A vibrational anomaly is observed in the thermal expansion behavior of Zr0„

in the temperature range from 930 C to the transformation temperature. There are

indications of a similar pretransformation vibration anomaly in Hf0„ in the range

from 1400 C to the transformation temperature.

(iii) In Zr0„ the length of the b axis remains almost constant below 500 C

2 ^ m

while the real expansion of the b axis occurs above this temperature.

(2) Monoclinic-Tetragonal Phase Transition in Zirconia

This investigation was aimed at a study of the mono-clinic-tetragonal transition

in Zr0

2 by high temperature x-ray diffraction at a number of test temperatures

maintained for sufficient time in the co-existence region. A careful study of the

positions and the intensities of the x-ray diffraction maxima in the coexistence region

was made to elucidate the mechanism of the transformation during heating and cooling in

84
terms of possible atomic movements and the sequence of changes

.

The monoclinic-tetragonal transition in ZrCL is spread over the temperature

930-1220 C during heating and 1030-700 C during cooling. Two distinct temperature

ranges are identified in the transition regions.

(i) pretransformation region, 930-1100 C and

(ii) co-existence region, 1100-1220 C, in which characteristic reflections

of both phases are present in the diffraction pattern.

An anomalous increase in the intensities of 111 and 111 is observed with in- m m

creasing temperature in the pretransformation region. The reflections 111 and 111

derive their intensities primarilyJ from Zr atoms , while 002 , 020 , and 200 depend

m' m' m

v mostly on oxygen atoms for their intensities. The anomalous increase in intensities,

prominent for 111 and 111 and slight in case of 002 ,020 , and 200 , is interpreted m m

a m m m

r

as a result of Zr atoms coming more and more in phase after changes in their positional

parameters because of their vibrational excitation due to special modes. The anomalous

expansion in selected d values in this temperature range serves as an additional

support for the existence of special vibrational modes in this region.

In the coexistence region it is more appropriate to think of hybrid crystal

formation rather than phase separation for the following reasons

(i) Only one reflection, 101. , characteristic of the tetragonal form appears

at 1110 C, while other lines appear at 1160 C or above. Similarly even

after the disappearance of the high index monoclinic lines at about 1190 C,

111 and 111 persist upto 1220°C. m m - ^

(ii) With increasing temperature in the coexistence region, many interplanar

spacings of the tetragonal form show a contraction instead of the usual

thermal expansion to be expected in the case of a distinct phase. Other

important characteristics of this hybrid crystal are:

(a) All reflections present in the diffraction pattern can be indexed

on either monoclinic or tetragonal structures and neither extra lines

,

if any, characteristic of this hybrid crystal structure nor any superstructure lines have been observed.

(b) 111 , 111 , and 101 show interdependence in their temperature dependent

intensities in the coexistence region.

85
Although these observations seem to favor the view of possible hybrid crystal

formation as a unique, ill defined structure rather than that through coexisting

domains, single crystal data are necessary to shed further light on this problem.

The orientation relationship between the two structures is now established as follows

:

(100) || (110). m ' t

C010]m )| [ooi]

t

A closer look at the coexistence region in the monoclinic-tetragonal as well as

tetraganol-monoclinic transition revealed the validity of the concept of hybrid crystal

formation in the coexistence region. It is seen that there exist two distinctly

different mechanisms for the transition in ZrO„ in the two cases of heating and cooling. During heating the Zr atoms are vibrationally excitable and the pretrans formation behavior is observed. This gives rise to a considerable spread of the transformation before the transition temperature. On the other hand, during cooling the

pretransformation behavior is absent and there is a drastic change in a small temperature range near the transition temperature indicating the instability of the high

temperature phase as a whole. This is interpreted as a cooperative change in both

short and long range interactions. This distinct difference in mechanisms of the

transition, one locally started during heating and the other cooperatively started

during cooling, is plausibly suggested to be the origin of the large thermal

hysteresis.

(3) Hysteresis and Kinetics of Zr0„ transformation

Thermal hysteresis and kinetics of the reversible monoclinic-tetragonal transformation in Zr0„ have been studied by DTA. The experimental variables used were

heating and cooling rates , number of heating and cooling cycles , the maximum temperature to which the specimen was heated and the time for which it was held at that

temperature. X-ray line broadening studies were also made to estimate the crystallite

size of the heat treated specimens. It has been observed that the crystallite size

increases quite fast with increasing the maximum temperature to which the specimen

was heated during the experiment and also with increasing time of holding at that

temperature. The magnitude of the thermal hysteresis for the transformation decreases

with increasing crystallite size. However the temperature of the forward

86
transformation is nearly invariant (1170 ± 10 C) , while the reverse transformation

occurs at 850 C in a specimen having finer crystallites (450 A) but increases to

1000 C when the crystallite size becomes more than 1200 A.

DTA technique has also been used to differentiate between the isothermal and

athermal kinetics of the transformation. It has been observed that isothermal kinetics are exhibited by specimens having smaller crystallites. However, athermal

behavior begins to appear as the crystallite size increases. It has also been

found that the annealing of the high temperature tetragonal phase resulted a sudden

vertical rise which took place within 2-3 seconds in the DTA peak in the cooling

direction. Zr0

9 transformation is believed to be martensitic in nature and the

phenomenon has been attributed to a burst like phenomenon generally observed in some

metallic systems. As expected, the Dhenomenon was observed only when the tetragonal

phase was annealed sufficiently by either increasing the annealing time at a lower

temperature or exposing it to a higher temperature so that the transformational

strain produced during the forward transition is removed and the martensite nuclei

can grow rapidly without encountering any immediate obstacles. At times a number of

smaller bursts were also observed. The extent of the major burst depends on the

amount of strain remaining in the specimen.

(4) Martensitic Transformation in Zirconia

The material presented above has added important information to the extensive

literature available on the phase transformation in zirconia. However, some inconsistencies have been pointed out by Weber. The nature of the transformation was not

clear. For example, Murray and Allison explained the observed kinetics in terms of

the classical nucleation and growth phenomenon, while Wolten was the first to suggest

that the tetragonal-monoclinic phase transformation is martensitic in nature. He based

this on the athermal and diffusionless behavior and on the large thermal hysteresis

,

which he attributed to a shear-type mechanism. A critical evaluation of the experimental data on the monoclinic-tetragonal transformation of Zr0o was undertaken, which

led to the conclusion that this transformation exhibits many of the characteristics

observed in martensitic transitions in metallic systems. This transformation is

accomplished by a diffusionless , shear-type mechanism, in which some atoms move by

87
distances less than an interatomic distance while other atoms nearly retain their

original positions . An orientation relationship exists between the two phases as

follows

:

(100) (110). . m I

' ret

[010] ,' [001] m 1 ! fct

The habit planes are reported to be (106) and (010) . The high temperature phase

is non-quenchable. Well-crystallized material exhibits athermal kinetics and small

crystallites undergo isthermal transformation. The critical crystallite size for

_5 athermal behavior is of the order of 10 cm. In well-annealed samples, the

tetragonal-monoclinic transformation takes place with a burst. The forward and

reverse transitions have a thermal hysteresis of 150-300 C in the case of Zr0„. It

is possible to obtain the high temperature tetragonal phase at room temperature in

a metastable state either by the application of hydrostatic pressure or by the

presence of small crystallite sizes obtained by special preparation techniques . Still

finer crystallite sizes result in the appearance of metastable cubic Zr0„ at room

temperature. On heating, these metastable phases revert to the stable forms.

The review concludes by identifying areas in which further work is needed.

B. Phase diagram studies on the system Zr0„ - Y0, ,-

(1) Subsolidus relations in this system at room temperature were determined from

studies on samples made by pressing the powders and sintering the pellets at 2000 C.

The system consists of three single phase solid solutions - one monoclinic and two

cubic, and two two-phase regions at room temperature. The system can be conveniently

divided into five regions

:

(a) Monoclinic Zr0

? solid solution: Our results show that a maximum of

3 mole % Y0, _ (1.5% Y-0-) can dissolve into the monoclinic phase of Zr0„.

(b) Fluorite-type cubic Zr0„ solid solution: This is the phase of greatest

technological interest. We have found 13 mole % Y0-, r (7% Y„0„) as the lower

l.o I i limit. The upper limit was found to be 71% Y0

5 (55% Y0J, Although lattice

parameter measurements were not made for this solid solution, it can be inferred

from the shift of the peaks that unit cell dimension increases with Y0-, r content,

since Y ion (0.92 8) is larger than Zr

+ ion (0.79 R) .
(c) Region of coexistence of monoclinic and cubic ZrO„ solid solutions:

The limits of this region are discussed in (a) and (b) above. We have

not found the earlier reported two phase region of monoclinic and tetragonal

Zr0

2

.

(d) Single phase YO, - solid solution was found from 90 to 100% YO, ,-

(82 to 100% Y„0J. The lattice parameter decreases with increasing Zr0„

content for these solid solutions.

(e) Coexistence of two cubic solid solutions: Fluorite type cubic Zr0

9 solid solution and cubic Y0, ,- solid solution coexist between the limits

discussed in (b) and (d) above.

(2) DTA studies on the system ZrO - Y0,

Zr0„ - Y0, r compositions with Y0, _ contents of - 8%, which had previously

been sintered at 2000 C for 5 hours were subjected to differential thermal analysis

with alumina as reference. Using weighed amounts of samples and reported values for

the heat effect at the monoclinic tetragonal transformation in pure well sintered

zirconia, an estimate of the heat effect at the transformation was made.

(i) At room temperature the monoclinic zirconia solid solution exists from

to 3 mole % Y0, ,-• A two phase mixture of monoclinic Zr0„ solid solution

and cubic solid solution exists for compositions containing between 3 and 13%

Y01.5-

(ii) The monoclinic-tetragonal transformation temperature (1170 C for pure

Zr0

2

) is reduced with the addition of YO-j^ 5 ud to a eutectoid composition and

temperature. The eutectoid transformation (tetragonal Zr0

9 solid solution -

monoclinic Zr0

? solid solution + cubic Zr0 9 solid solution) is located at about

565 C and about 7.5 mole % Y0, r- There is an increase in the magnitude of

heat effect at thermoclinic-tetragonal transformation upto 2 mole % Y0, _ and

then a decrease. The peak of the curve nearly coincides with the limit of

solid solubility of Y0, r in monclinic Zr0

9

. The magnitude of the heat effect

for other compositions is approximately proportional to the amount of the

monoclinic phase in the two phase field.

89
C. The ternary system ZrO - Y - Nb

Ternary compositions from this system with varying zirconia-yttria ratios at constant

niobia contents of 3,5 and 10 % respectively were made by pressing and sintering at 2000 C.

The following facts are obtained from the diffraction patterns of these compositions

:

(a) On the 3% niobia line cubic fluorite phase extends from 7% yttria to between

45% and 49% yttria.

(b) On the 5% niobia line fluorite phase extends from between 15% and 20% yttria to

between 45% and 50% yttria.

(c) On the 10% niobia line fluorite phase extends from between 20% and 25% yttria to

between 40% and 45% yttria.

Thus the cubic fluorite type solid solution phase field has a dome-shaped appearance

in the ternary system.

In all the above cases a two phase region of monoclinic solid solution and fluorite type

s.s. exists on the low yttria content side of the phase diagram. A two phase region of

fluorite type s.s. and s.s. of zirconia in yttria appears on the high yttria content side

of the phase diagram.

Accurate lattice parameter determinations were done for ternary compositions . The

lattice parameters gradually increase with yttria content for any fixed niobia content.

This is in accordance with the ionic size consideration for zirconium (0.79 A) and yttrium

(0.92 A). The lattice parameter for compositions with a fixed zirconia content decreases

with increasing niobia content. This is to be expected because the ionic radius of niobium

(0.69 A) is smaller than that of yttrium. The lattice parameter values are consistent with

the cubic solid solution field boundaries as established by the disappearing phase method.

The lattice parameter variation with yttria content shows a negative deviation from

Vegard's law. But the lattice parameter variation with niobia content show a positive

deviation from Vegard ' s law

.

D. Phase diagram and conductivity studies in Th0„ - CaO system

We took up investigations to study the defect structure and its effect on the electrical

properties of ionic solids with the fluorite structure. For this we chose thoria in the

pure and CaO doped conditions.

90
The phase diagram ThCL-CaO is not well established. The first attempts were to find out

the solubility limit of CaO in Th0

9

. Samples were made by pressing mixtures of Th0

9 and

CaCOo powders and sintering at 2000 C. The solubility limit was found out both by the

disappearing phase method as well as by lattice parameter determinations. The lattice

parameter shows a decrease from mole % CaO to 5 mole % CaO. Thereafter it remains

constant showing that the solubility limit is between 5 and 10 mole % CaO. This view is

supported by the x-ray patterns as one line corresponding to CaO phase appears in the

samples containing 10% or more of CaO, while it is absent in samples with less CaO content.

A.C. Electrical conductivity at 1 KHz was measured for samples with 0,1,2,3,4,5,6 and

10 mole % CaO, at 50 C intervals in the temperature range 600 to 1350°C. The conductivity

of all the samples can be represented by an Arrhenius type equation:

a(T) = A exp ( -E/kT)

in major part of the temperature range.

5 5 Values of the constant A lie between 0.06 x 10 and 1.24 x 10 and the values of the

activation energy E are in the range 1.12 to 1.18 ev. The isothermal conductivities for

these samples show an increase with CaO content from to 4 mole % CaO and then remain

constant after a slight drop. The activation energies may be taken to be constant within

experimental errors. It is observed that the conductivity goes through a maximum at about

the composition with 2% of anion sites vacant. This fact is in agreement with the observation on other Th0

9 based solid solutions where a conductivity maximum is observed in compositions with 2 to 3.5% anion sites vacant.

E. X-ray diffraction and conductivity studies on YJ3.-, solid solutions:

Phase diagram and electrical conductivity studies were done on compositions near the

Y 0» end of the Zr0„ - Yr0„ - Y system. Samples were made by mixing powders of Zr0„ and

Y„0. in the required ratio and sintering them twice at 2000 C with intermediate grinding

and pressing.

The solid solubility limit of Zr0„ in Y 0, was determined by precise determination of

lattice parameters and microstructural studies. The lattice parameter decreases with

addition of Zr0

2 to Y0. for 10.603 8 (pure Y ) to 10.568 8 at 18% ZrO content beyond

which it remains constant showing a two phase region. This is confirmed by the microstructure of the single phase and two phase compositions on the two sides of the composition

91
at 18% ZrO in Y CL. A. C. Electrical conductivity at 1 KHz was measured in the temperature range 700 C to 1250 C. The values of log G vs. 1/T can be represented by two straight

lines of different slopes in the low and high temperature regions.

The activation energies in the extrinsic region i.e. the low temperature region is

about 0.21 ev. while it is about 1.7 ev. in the intrinsic region i.e. the high temperature.

It is suggested that in both the extrinsic and intrinsic regions the defects responsible for electrical conduction are fully ionized yttrium vacancies that generate compensating

holes. In the extrinsic region the yttrium vacancies are created by the substitution of

3+ 4+ Y by Zr ions. Thus conduction is impurity controlled in the extrinsic region, as

evidenced by the increase in conductivity with Zr0„ content.

In the intrinsic region, the yttrium vacancies responsible for conduction are those

created due to existence of a Schottky defect situation in thermal equilibrium. The "Knee"

temperature for each composition represents the temperature at which thermally generated

yttrium vacancies far out number those due to impurities. The shift of the "Knee" to higher

temperatures with increasing Zr0„ content is in accordance with expectations according to

this model.

F. Defect calculations in fluorite lattice

Most solid solutions of high temperature oxides such as Zr0

9

, U0„, Th0„ etc. have

fluorite lattices. Also, the electrical conductivities of such materials are known to be

ionic. It was thought, therefore, that detailed defect energy calculations on CaF„ lattice

would help to build up a model for explaining the transport mechanisms involved in these

oxides

.

Some calculations were carried out on CaF_ lattice of the activation energies of

migration of anion vacancies as well as anion interstitials . The method used was that

developed by Franklin. Results showed that the anion vacancy movement occurs along the

(100) direction of the lattice. Also, an interstitialcy mode of anion motion is the

likely mechanism of transport in lattice having interstitial anions.

The preliminary results have been published.

G. Papers presented at conferences based on work on the project

1. R. N. Patil and E. C. Subbarao, "Studies on the Thermal Expansion Behavior of the

Refractory Oxides Zr0„ and Hf0„ by x-ray Diffractometry , " at the 32nd Annual meeting

of the Indian Ceramic Society, Madras (July 1968).

92
2. C. B. Choudhary and E. C. Subbarao, "Cubic Fluoride Type Phase in the Systems ZrCL -

Y 0, - Nb„0 " at the 33rd Annual meeting of the Indian Ceramic Society, New Delhi,

(March 1969).

3. R. N. Patil and E. C. Subbarao, "X-ray Diffraction Study of the Monoelinic-Tetragonal

Phase Transition in Zirconia," at the VIII International Congress of Crystallography,

Stony Brook, New York (August 1969). For abstract, see Acta Cryst.

H. Papers in course of preparation

1. E. C. Subbarao, H. S. Maiti, and K. K. Srivastava, "Martens itic Transformation in

Zirconia," (to be published).

2. K. K. Srivastava, R. N. Patil, C. B. Choudhary, K.V.G.K. Gokhale, and E. C. Subbarao,

"Revised Phase Diagram for the system ZrCU-YO-, " (to be published).

I. Theses based on work on the project

1. C. B. Choudhary, "Cubic Fluorite-type Phase in the System ZrCL - Y - Nb ,"

M. Tech. Thesis, ITT Kanpur (January 1969).

2. C. S. Krishnan, "Some' Studies on Y - Zr0

2 System," M. Tech. thesis, I IT Kanpur

(January 1969).

3. A. K. Mehrotra, "Electrical Conductivity of the system ThCL - CaO," M. Tech. Thesis,

IIT Kanpur (January 1971).

List of Publications that Resulted from the Project

1. R. N. Patil and E. C. Subbarao, "Axial Thermal Expansion of Zr0

? and Hf0„ in the Range

Room Temperature to 1400°C," J. Appl. Cryst. 2, 281-288 (1969).

2. R. N. Patil and E. C. Subbarao, "Monoelinic-Tetragonal Phase Transition in Zirconia:

Mechanism, Pretrans formation and Coexistence," Acta Cryst. A 26 , 535-542 (1970).

3. E. C. Subbarao, C. B. Choudhary, A. K. Mehrotra, and R. N. Patil, "Defect Structure

and Ionic Conductivity of Zirconia and Thoria," Proc. Symposium on Materials Science

Research, Bangalore, Vol. I, 429-435 (February 1970).

4. D. Chakravorty, "Energy of Migration of Anion Vacancy and Interstitial in Calcium

Fluorite," J. Phys. Chem. Solids, 32_ 1091-1092 (1971).

5. C. S. Krishnan and D. Chakravorty, "Electrical Conductivity in Cubic Y_0o - Zr0„ Solid

Solutions," Mat. Res. Bull. 6, 91-96 (1971).

93
6. H. S. Maiti, K.V.G.K. Gokhale, and E. C. Subbarao, "Kinetics and Burst Phenomenon in

Zr0

2 Transformations," J. Am. Ceram. Soc. , _55, 317-322 (1972).

7. H. S. Maiti, K.V.G.K. Gokhale, and E. C. Subbarao, "Effect of Heat Treatment on the

Kinetics of Zirconia Transformation," Proc. Symposium on Materials Science Research,

Hyderabad, 353-363 (February 1972).

94
B.I.* MATERIALS SCIENCE AND TECHNOLOGY

Project Title : TRANSPORT PROPERTIES OF SOLIDS AT LOW TEMPERATURES

Principal Investigator : Dr. G. S. Verma (Present address: Physics Department

Banaras Hindu University

Varanasi 5 UP, India)

Institution : Physics Department, Allahabad University, Allahabad

NBS Monitor : Dr. A. H. Kahn

NBS Institute or Center and Division : Institute for Materials Research

Inorganic Materials

Summary Description of Project Goals

The aim was to examine critically and evaluate the role of different phonon scattering

processes in thermal transport properties of solids , especially insulators and semiconductors, in the low and high temperature regions.

Results and Implications to Date

A. Thermal transport properties of solids

Simplified expressions for the resonance-scattering relaxation rates for phonons for

doped Ge have been obtained for the first time for situations hco \>>4A, K,T» 4 A and

hwqA<<KT and KT <<4A, where 4A is the energy difference between the donor electron singlet

ground state and the first higher energy triplet state [25] . Hasegawa's angular matrices,

which depend upon the geometrical structure of the conduction band, are obtained for Ge.

These expressions have been very successfully used in explaining the low temperature phonon

conductivity results of Sb-and As-doped and compensated Ge in the off-resonance situations

where other phonon scattering processes are also relevant. For doped alkali halides , where

the nature of the coupling of the rotational states of the impurities to the phonons is not

fully understood, the frequency dependence of the resonance relaxation rates have been

established for CN and N0

? doped alkali halides [18]. Kwok's theory has been modified by

including the transitions to the singlet and triplet states from higher energy states which

are relevant at higher temperatures . With this modification a partial success has been

achieved in explaining the discrepancy between Kwok's theory and the observed temperature

dependence of acoustic phonon attenuation in P-doped Ge beyond its maximum [24].

* The alphanumeric designation refers to the NBS Program Structure (see Appendix II). ** Figures in brackets refer to the List of Publications that Resulted from the Project.

95
It has been established quantitatively for the first time that for donor electron

17 3 concentrations greater than 10 /cm , Ziman scattering of phonons by electrons in the

conduction state is responsible for the drastic reduction in the phonon conductivity of

Sb-and As-doped Ge. For these heavily doped semiconductors, impurity levels merge with

the conduction band. However, in establishing this fact we had to consider the temperature

dependence of density-of-state effective mass and the reduced Fermi potential. Fortunately

the information regarding the temperature dependence of the reduced Fermi potential was

obtained from the thermoelectric data of the same samples. The above conclusions were

verified for a large number of Sb-and As-doped Ge samples. The large decrease in the

phonon conductivity with the increase in the donor electron concentration is explained in

terms of the increase in the deformation potential.

Nowhere in the literature one will find calculations in such a comprehensive scale for

the thermoelectric power for113 n* (reduced Fermi potential) varying from -22 to +38 and the

. scattering parameter S= -

2 ,0, +2 ,+l and +2

. The point of these calculations is that if

one knows or assumes the nature of the scattering of the electrons by phonons one can read

directly the values of the reduced Fermi potential from the graphs for the observed values

of the thermoelectric power. Values of F , Fi/ 2 , Fj , F 3 / 2 , F2 , F 5 / 2 , F 3 and F4 for n"

varying from zero to +40 and that of Fw 2 and F3 / 2 for n * varying for zero to -24, were

not available. These have been calculated for the first time and are available on request.

It was further established that Carruthers ' scattering , in which phonons are scattered

as a result of virtual transitions of the donor electrons between the ground state and threefold degenerate first excited state, can explain the drastic reduction in the phonon con17 _3

ductivity of those samples for which the donor electron concentration is less than 10 cm .

Values of the shear deformation potential as obtained from the phonon conductivity data are

found to lie between 17.8 and 27.9 eV.

It has been shown for the first time that diopolar contributions to thermal resistance

due to electrons and holes become important in the lattice thermal conductivity of doped

Si-Ge alloys at high temperatures. The phonon conductivity of both n- and p- type Si-Ge

alloys with different carrier concentrations has been estimated by calculating separately

the contributions of longitudinal phonons and transverse phonons. It has been found that

there is good agreement between the calculated temperature dependencies of the total phonon

96
conductivity and the experimentally obtained values of thermal conductivity minus electronic

conductivity. The dilatational deformation potential is found to increase with the increase

in the carrier concentration and the reduced Fermi potential. The dipolar contribution is

found to be significant at temperatures above 700 K for n-type alloys , for which the doping

is comparatively low.

In insulators the transport of energy takes place through phonons and heat conduction is

adequately described by the interaction between the phonons , impurities , and imperfections

.

In ferromagnetic insulators at sufficiently low temperatures magnons can also act as the

carrier of heat energy. This aspect of phonon conductivity due to magnons has been considered by Sato, Douthett and Friedberg, Harris and Luthi, and Douglass. But all of them

neglected magnon-phonon interaction. They considered that magnons and phonons are scattered

only by boundaries of grains or of the specimen. Expressions have been derived for magnonphonon scattering relaxation times for different cases as a function of temperature and wave

vector using the theory of Sinha and Upadhya. The appropriate relaxation time is used in

the determination of the effective relaxation time for magnons and thermal conductivity of

YIG is calculated in the temperature range 0.5 to 70 K considering a quadratic dispersion

law for magnons and a Debye spectrum for phonons. Scattering of magnons by defects is also

considered. The magnon contribution is shown to be appreciable in the temperature range

0.5 to 2 K. [19].

Values of the nonlinearity constant D , which involves third-order elastic constants

,

are obtained for silicon from the phonon conductivity data in the presence of point-defect

scattering. The results are compared with the theoretical value obtained on the basis of

Keating 's theory which has been very successful in explaining the third-order elastic

constants of Si. It has been shown for the first time that the constant D depends upon

temperature and the assumption by the previous workers that it is independent of temperature is not correct. Keating' s theory overestimates the value of the non-linearity constant

[16]. A similar study for Ge at room and liquid nitrogen temperatures reveals the temperature dependence of D [26]. It is found that Keating 's theory fails to explain the third

order elastic constants of GaAs as it omits the effect of long range Coloumb forces on

harmonic constants [17].

97
B. Subsidiary work

Solid state acoustics: For the first time the acoustic saturation of individual NMR

lines were studied. A generalized expression for the central resonance line corresponding

to the ultrasonic transition probability W " is obtained for an arbitrary spin I. This

expression, which is same for quadrupolar and pure magnetic relaxations is given by

N

l

- N

-l

2 = n

o

f

32W " T 1 -1

t

1 + Po + -rm5 2" J

where W " W 31W1 3W3 1 W 1 3 T, is the nuclear spin- u2= u^---2= u2""

1

2

= u

2 ""2 = u "2^2' 1 lattice relaxation time and P - ^ is a measure of the radio frequency transition probabilityJ W. > - = W jii - 1 + in = (P -i)W(I + m)(I-m + l). The effect of the rfm m 1 rf m 2 acoustic power on the satellites for the different cases is studied in great detail. Some

of the affected satellites show interesting behavior in the sense that, instead of the

regular saturation behavior, enhancement effect and negative ratios of the population

difference to its equilibrium value are obtained for higher values of U, which is a measure

of acoustic power [4].

The basic ideas of the jump diffusion model are applied to nuclear spin-lattice relaxation in water and information regarding the influence of temperature on the nature of

diffusive motion in water has been obtained. The number of the solid- like vibratory modes

initially decreases rapidly as the temperature is increased from C and at about 40 C it

drops to a value which remains constant up to 92 C. At room temperature about 40% of the

modes are Langevin type and the rest solid like. As many as 50% of the modes of vibration

are still solid like near the boiling point. By assuming that the time T during which a

molecule stays at a site and performs complicated vibratory motion is the shear relaxation

time, values of shear modulus in water at different temperatures and pressures are

obtained [3].

A random walk model is applied to dipolar relaxation via atomic diffusion in a bcc

lattice containing two nuclear species. Expressions for T, and T„ in the high field and

low temperature limit as well as high temperature and low field cases are derived for

magnetic field along (100) and (110) directions. For example, for a magnetic field applied

along the (100) direction and the high field and the low temperature limit

98
T\ 1 =8.99 ATa

6 v T

u>_ 2 +A a

6 (v T v+ v ) [0.149 UT-u> ) 2 +11.124a),

2 +12.105 (co T

+co )" 2

] 1 loll sols Is I Is

T

~ 1 =8.31 ATa" 6 v"1 +0.56A a~ 6 (v T + v ) _1

2 Iol sols

where

AT

= v T VT (I + l)f_, A = v T

2

v

2h2 III Isis s (s + l)f

s

Here r, w, f and x> are the gyromagnetic ratio, resonance frequency, fractional isotopic

abundance and jump frequency, respectively. The subscripts I and S refer to the two nuclear

species of spin I and S , a is the cube edge

.

List of Publications that Resulted from the Project

1. D. P. Tewari and G. S. Verma, "Some Comments on the Diffusive Motion and Nuclear Spinlattice Relaxation in Water," Nuovo Cimento, 34, 1638 (1964).

2. D. P. Tewari and G. S. Verma, "Acoustic Saturation of Nuclear Magnetic Resonance Lines,"

Nuovo Cimento, 38., 197 (1965).

3. CM. Bhandari and G. S. Verma, "Thermal Conductivity of Ge-Si Alloys at High Temperatures," Phys. Rev. 138, 4288 (1965).

4. N.K.S. Gaur and G.S. Verma, "Conductivity Effective Mass from Far Infrared Reflection

Measurements," Physica 31, 1489 (1965).

5. C. M. Bhandari and G.S. Verma, "Role of Transverse and Longitudinal Phonons in Thermal

Conductivity of InSb and GaAs," Phys. Rev. 140, A2101 (1965).

6. N.K.S. Gaur, C. M. Bhandari, and G.S. Verma, "Temperature Dependence of Density-ofStates Effective Mass and the Electronic and Phonon Contribution to Thermal Resistance

of Doped Si-Ge Alloys at High Temperatures," Phys. Rev. 144, 628 (1966).

7. N.K.S. Gaur, C. M. Bhandari, and G.S. Verma, "Resonance Scattering of Phonons in GaAs,"

Physica 32_, 1948 (1966).

8. N.K.S. Gaur and G.S. Verma, "Temperature Dependence of the Effective Electron Mass in

n-InAs," Physica 32_, 1110 (1966).

9. C. M. Bhandari and G.S. Verma, "Role of Magnons and Phonons in the Thermal Conductivity

of YIG," Phys. Review, 152 , 731 (1966).

10. N.K.S. Gaur and G.S. Verma, "Infrared Absorption due to Donor Electrons in Semi-conductors," J. Phys. Soc. Japan, 21, 1880 (1966).

99
11. C. M. Bhandari and G.S. Verma, "Influence of Point Defects on Phonon-Drag ThermoElectric Power," Nuovo Cimento 47, 129 (1967).

12. N.K.S. Gaur and G.S. Verma, "Electron-Phonon Scattering in n-type Ge at low Temperatures," Phys. Rev. 159, 610((1967).

13. A. Kumar, A.K. Srivastava, and G.S. Verma, "Resonance Scattering of Phonon in KC1:CN,"

VII Conference on Thermal Conductivity, NBS, Washington, D.C., Nov. 13-16 (1967).

14. N.K.S. Gaur and G.S. Verma, "Phonon Drag Thermoelectric Power in Dilute Alloys of

Copper," Physics Letters, 264 , 183 (1968).

15. R.P. Singh and G.S. Verma, "Validity of Nernst-Lindemann Equation in the Range

24° - 1200°C in Tungsten," Solid State Communications, 5_, 2, 113 (1968).

16. R. P. Singh and G.S. Verma, "Phonon Conductivity and Acoustic Attenuation in Si,"

Physical Rev. 171, 838 (1968).

17. R.P. Singh and G.S. Verma, "Keating' s Theory and Third-order Elastic Constants of

GaAs," J. Appl. Phys. 39_, 4032 (1968).

18. A. Kumar, A. K. Srivastava, and G.S. Verma, "Resonance Scattering of Phonons in

CN-doped Alkali Halides I," Phys. Rev. 178, 1480 (1969).

19. A. Kumar, A. K. Srivastava, and G.S. Verma, "Resonance Scattering of Phonons in KC1

and KBr, doped with NO -ions II," Proc. Phys. Soc. (Japan), _25, 1204 (1969).

20. CM. Bhandari and G.S. Verma, "Magnon-Phonon-Drag Thermoelectric Power," Nuovo Cimento,

60B, 249 (1969).

21. Y.P. Joshi, M.D. Tewari, and G.S. Verma, "Density-of-states Effective Mass at Low

Temperatures in Sb-doped Ge," Physics Letters, 304, 89 (1969).

22. R. C. Tripathi, CM. Bhandari, and G.S. Verma, "On the Temperature Dependence of the

Bulk Modulus of some Diatomic Halides," Physica, 45, 332 (1969).

23. Anil Kumar and G.S. Verma, "Phonon Conductivity of Mg

2Sn," Phys. Rev. 1, 488 (1970).

24. A. K. Srivastava and G.S. Verma, "Temperature Dependence of Acoustic Phonon Attenuation

by Bound Donor Electrons in Ge," Phys. Rev. 1, 776 (1970).

25. Anil Kumar, Arun Kumar Srivastava, and G.S. Verma, "Scattering of Phonons by Bound

Donor Electrons in Doped Germonium," Phys. Rev., B2^, 4903 (1970).

26. R. C Tripathi and G.S. Verma, "On the Third Order Elastic Constants of Ge at Room and

Liquid Nitrogen Temperatures," J. Appl. Phys. 41, 2999 (1970).

100
27. G. S. Verma, C. M. Bhandari, and Y.P. Joshi, "Longitudinal and Transverse Phonons

in the Lattice Thermal Conductivity of GaAs and InSb, 4 Reply," Phys. Rev. B3,

3574 (1971).

101
B.3.* BUILDING TECHNOLOGY

Project Title : COMPOSITE STRUCTURAL SYSTEMS IN BUILDINGS

Principal Investigator : Dr. J. K. Sridhar Rao

Institution : Indian Institute of Technology, Kanpur

NBS Monitor : Dr. E. 0. Pfrang

NBS Institute or Center and Division : Institute for Applied Technology

Center for Building Technology

Summary Description of Project Goals

The following specific topics in "''Composite Structural Systems in Buildings" are to

be investigated:

1. A comprehensive review of the state of the art of all aspects of structural

behavior, fire proofing, elastic and inelastic behavior, shrinkage, temperature

and fatigue considerations of structures and structural components.

2. Annotated Bibliography.

3. Experimental and analytical studies on the following types of structures/

structural components

:

(a) Infilled Frames

(b) Masonry Walls on Beams

(c) Encased Beams in Columns and Infilled Tubes

(d) Continuous Beams with Particular Reference to Reinforcement in the Negative

Moment Region

4. Mathematical studies would be carried out using discrete analytical models for

continuous systems, and also using numerical techniques.

Results and Implications to Date

1. A review of existing literature indicates that while a considerable amount of work

has been done all over the world on steel - beam - concrete slab interaction with

various types of shear connection, a complete picture of composite action in infilled frames , slabs on steel girds , interaction of frame - slab - wall systems

etc. , cannot be presented at this time.

A comprehensive review of the state of the art was thus restricted to steelconcrete beams and a report (300 pages) has been prepared covering (a) Shear

* The alphanumeric designation refers to the NBS Program Structure (see Appendix II).

102
connectors, (b) Behavior of composite beams in bending, (c) Elastic analysis and

design, (d) Ultimate strength procedures for analysis and design, (e) Limit states

and safety factors, (f) Creep, shrinkage and temperature effects, (g) Fatigue and

repeated loading effects, (h) Economy of composite beams, and (j) Recommendations

for further research. Certain advanced "Computer Studies" on various aspects of

interaction are also appended. It is felt that this comprehensive review will be

of use to text book writers.

2. An annotated bibliography of nearly 700 references has been prepared. References

have been collected up to June 1972.

3. Tests and analytical studies on infilled frames were omitted on the advice of

Dr. E. 0. Pfrang, Chief, Structures Section, NBS and attention was focussed on

walls on beams , encased beams , encased columns , continuous beams and stud shear

connectors. The following full scale tests were completed:

(a) Push out tests - 32 specimens

(b) Column tests - 18 "

(c) Encased beams - 7 "

(d) Continuous beams - 6 "

(e) Walls on beams - 17 "

Besides these a large number of control tests on bricks, brick wallettes , mortar,

concrete and steel were conducted.

The following reports detailing the experimental findings , computer programs

,

analytical studies, and theoretical predictions have been completed:

(a) Behavior, analysis, and design of composite columns (Encased steel sections

in concrete )

.

(b) Stength and behavior of shear connectors under static and pulsating loads.

Analysis of experimental data for the following areas have been completed

and the final report is awaiting the completion of computer calculations

(a) Walls as beams

(b) Encased beams

(c) Continuous beams

As a contribution to the area of "Composite Structural Systems in Buildings"

the large amount of test data collected can be mentioned. These data throw light

103
on areas not already investigated by previous research workers. The computer programs

generated in the course of analytical investigations using IBM 7044- system will be

of assistance to other investigators. As an additional outcome from this project can

be mentioned the benefit given to ten graduate students of IIT Kanpur, who would not

otherwise have undertaken advanced studies.

List of Publications that Resulted from the Project

1. J. K. Sridhar Rao and C. V. S. Kameswara Rao, "Statistical Aspects of Strength and

Fracture Behavior of Concrete," in "Proceedings of the International Conference on the

Mechanical Behavior of Materials, Kyoto, Japan; "Society for Materials Science, Kyoto,

Japan (1972).

2. S. R. Parimi and J. K. Sridhar Rao, "Effectiveness of Random Fibres in Fibre Reinforced

Concrete," in "Proceedings of the International Conference on Mechanical Behavior of

Materials, Kyoto, Japan," Society for Materials Science, Kyoto, Japan (1972).

104
B.3.- BUILDING TECHNOLOGY

Project Title : STUDY OF STRUCTURAL ELEMENTS UNDER DYNAMIC LOADING

Principal Investigators : Professor V. Sundararajan and Dr. V. Kadambi

Institution : Indian Institute of Technology, Kanpur

NBS Monitor : Dr. E. 0. Pfrang

NBS Institute or Center and Division : Institute for Applied TechnologyCenter for Building Technology

Summary Description of Project Goals

The research was directed towards an experimental and theoretical investigation of

the effects of blast loads on structural elements and structural models . The experimental

study was to be concerned with the development of methods of stress and strain measurement

in elements under dynamic loading conditions . Theoretical investigations were to be made

on the inelastic response of structural systems subjected to blast loads.

Results and Implications to Date

The following investigations have been completed to date:

1. Analysis of transverse impact behavior of simply supported and built-in beams

is investigated with and without taking into account the contact deformation.

The impact is assumed to be elastic, and Hertz's law of contact deformation

is assumed to hold. Experiments have been conducted to verify theoretical

predictions. Non-dimensionalized impact force and maximum strain have been

plotted against impact parameter which depends on the geometries and the elastic

properties of the beam striker.

2. The response of simply supported and clamped beams partially subjected to blast

loads has been studied. In the theoretical analysis different types of pressure

distribution in shock waves have been considered. Experiments have been conducted

using a shock tube as a loading mechanism. The theoretical and experimental

results have been plotted in terms of a dynamic amplification factor and a nondimensionalized dynamic moment against the period ratio.

3. The response of a beam-column to various pulse loads applied symmetrically over a

definite span is being investigated analytically. Various types of transverse

transient loads are considered. The effect of pulse shape and the duration of the

I The alphanumeric designation refers to the NBS Program Structure (see Appendix II)

105
pulse on the response are studied. Numerical results for the responses in

terms of the dynamic amplification factor for the deflection and bending

moments are presented in a series of non-dimensional curves

.

4. The response to blast loading of thin plates with and without cutouts has

been investigated experimentally.

5. The elastic and inelastic response to blast loads of structural systems is

under continued investigation. The method of analysis is finite-element

idealization followed by numerical integration. The method when fully

developed will give the response (elastic as well as permanent deformation)

of an enclosure (for example a tank) in which an internal explosion occurs.

Both rigid-strain hardening and elastic-plastic material behaviors are yet

to be studied.

List of Publications that Resulted from the Project

1. V. K. Jadon, V. Sundararaj an , and L. S. Srinath, "Analysis of Transverse Impact on

Beams," Research report NBS-ME-1, Dept. of Mechanical Engineering, ITT, Kanpur

(Aug. 1971).

2. S. K. Banerjee and V. Sundararaj an , "Response of Beams to Blast Load," Research report

NBS-ME-2, Dept. of Mechanical Engineering, ITT, Kanpur (Nov. 1971).

3. B. Prasad and V. Sundararaj an , "Studies on the Blast and Impact Loadings on Beams,"

Research report NBS-ME-3, Dept. of Mechanical Engineering, IIT, Kanpur, (Dec. 1971).

4. A. Rajamani and V. Sundararaj an , "Dynamic Response of Plates to Blast Load," Research

report NBS-ME-M-, Dept. of Mechanical Engineering, IIT, Kanpur, (Aug. 1972).

106
B . 9

. * FAILURE AVOIDANCE

Project Title : STUDIES OF THE ELECTRICAL BREAKDOWN AT THE JUNCTION OF METALS AND SOLID

DIELECTRICS IN HIGH VACUUM AT HIGH VOLTAGES

Principal Investigator : Dr. H. V. Gopalakrishna

Institution : Indian Institute of Science, Bangalore

NBS Monitor : Mr. F. Ralph Kotter

NBS Institute or Center and Division : Institute for Basic Standards

Electricity Division

Summary Description of Project Goals

This project aimed at providing a better understanding of insulation breakdown at

the metal-dielectric junction in vacuum. In particular, the investigation was to cover

(a) Reproducibility of breakdown voltages and relation between length of dielectric and

breakdown voltage, (b) Relation between dielectric constant and breakdown voltage, (c)

The relative importance of anode vs. cathode conditions, (d) Studies with mixed electrodes,

different dielectrics with different geometries, and (e) Study of factors contributing to

the obtaining of more uniform electric fields or the highest performance for a given set of

conditions

.

The investigation could both be theoretical and experimental in nature in the high

vacuum region with high dc. ac, and impulse voltages.

Results and Implications to Date

The work carried out so far can be summed up under three categories as follows

(1) direct voltage breakdown, (2) breakdown under power frequency voltages, and (3) prebreakdown phenomena.

(1) Direct Voltage Breakdown

This investigation was conducted on three dielectric materials : polytetrafluoroethylene (PTFE), Polymethyl methacrylate (Perspex) , and unglazed electrical

porcelain in the form of 13.0 mm rods. The electrodes were of 304 stainless steel

25 mm in diameter and were used in the Diane-parallel configuration. Experiments

-4 -6 were conducted in vacua ranging from 10 Torr to better than 10 Torr.

" The alphanumeric designation refers to the NBS Program Structure (see Appendix II).

107
The first Dhase of the investigation concerned the reproducibility of

breakdown voltages over specimens approximately 5 mm thick, and the influence

of the methods used for preparing and conditioning the electrodes and specimen

to the breakdown voltage. A method of preparing and conditioning was arrived

at , which gave the very high breakdown gradients of 14.2 to 16 . 2 kV/mm for FIFE

,

11.0 to 14.8 kV/mm for Perspex and 5.7 to 6.7 kV/mm for porcelain. An inverse

relation of the breakdown gradient with the relative permittivity e of the

specimen became obvious. After taking into account the field intensification

at the junction caused by the presence of the dielectric by a factor g . , these

results have been shown to be in agreement with the constant breakdown gradient

criterion proposed by Alnert et al. for plain vacuum gaps. The factor 6- has

been called the junction field intensification factor and has a value such that

1^6- < e .

The dependence of breakdown voltage on specimen thickness was studied next.

An analysis of the results shows that, in general, three ranges of specimen

thicknesses exist separated by two transition values £„ and l „. Below 2TM, the

breakdown voltage is limited by the dielectric strength of the specimen. The

region between s> and t is a transition region in which the breakdown may be

limited by the dielectric strength or the negative junction phenomenon depending

on the negative junction field intensification. Above i „, the breakdown is

invariably caused by the negative junction phenomenon. For specimen thicknesses

greater than 9.^, the minimum breakdown voltage has been shown to be given by:

45 7 x £

- 6

V, = kV, where i is in mm. This expression may therefore be used r

as the criterion for the design of support insulators in vacuum. However, the

results show that to support even moderately high voltages , the insulators have

to be inordinately long. Therefore, four methods of improving the breakdown

voltages were investigated:

(a) Use of epoxy coated cathodes : For all the three dielectrics

substantial improvement in breakdown voltage was obtained by using epoxy

coated electrodes. This method has two significant advantages in that

spark conditioning for electrodes and glow discharge conditioning for the

108
specimen are obviated.

(b) Metallizing the contact area between the specimen and the electrodes :

With porcelain, this method resulted in excellent improvement in the breakdown

voltage. Metallization was by vacuum deposition of silver. However, with

Perspex there was little or no improvement. Strong coatings could not be

obtained with PTFE.

(c) Composite dielectric arrangment : The composite arrangement of a porcelain specimen and a thin wafer of PTFE at the cathode end gave breakdown voltages

corresponding to a single PTFE specimen of combined length. This method is

useful in improving the breakdown voltage over high permittivity support

insulators

.

(d) Cascaded insulator assembly : From the equation given above, the breakdown voltage is found to be nonlinearly dependent upon specimen thickness

.

Therefore, if a given vacuum gap is subdivided by metallic spacers and each subgap supported by insulators , the breakdown voltage would be the sum of the breakdown voltage of the individual gaps. This would then be more than the breakdown

voltage of a single insulator of the same total length. Experiments with two

and three subgap assemblies were conducted and the results indicate the necessity

for voltage grading when the number of subgaps is more than two.

(2) Breakdown Under Power Frequency Voltages

In order to compare the results obtained with direct voltages , experiments

with alternating voltages at power frequency were conducted with the same type

of electrodes and dielectric specimens under similar conditions. The breakdown

gradient for PTFE specimens decreased from about 15 kV/mm for a 2 mm thick specimen to 7.5 kV/mm for a 10 mm thick specimen. For Perspex, it decreased from

11 kV/mm (2 mm thick) to 6 kV/mm (15 mm thick) and for porcelain 7 kV/mm ( 2 mm

thick) to 4- kB/mm (20 mm thick). A comparison of the breakdown performance of

the solid dielectrics between ac and dc revealed the following: (i) The

breakdown voltage with ac for a given dielectric is generally lower than that

obtained with dc, (ii) The luminous glow on the surface of the dielectrics,

known as surface charging, is pronounced with ac, and (iii) Metallization of

109
the surface of the specimens in contact with the electrode surface has an

adverse effect on the breakdown voltage with ac. It should be noted that this

has a definite beneficial effect with dc in improving the breakdown voltage.

Thus the experimental results showed an inferior performance of the dieelectric materials with alternating voltage. A straightforward application

of the constant breakdown gradient theory of Alpert et al. for plain gaps with

direct voltage, does not seem to explain in full the breakdown phenomena with

alternating voltages. It was felt necessary that a study of prebreakdown

phenomena of clean gaps with ac may throw some light on the behavior of the

breakdown across solid dielectrics.

(3) Prebreakdown Phenomenon

With alternating voltages, the gap current consists of (i) a displacement

current , due to the gap capacitance , in quadrature with the applied voltage and

(ii) a current, in phase with the voltage, with a highly distorted waveform

and varying nonlinearly with the voltage. Measurements of the peak values

of the latter current were done at various voltages for different gap spacings

of 1 to 6 mm by the use of oscilloscopes. Similar measurements were also conducted with dc. The important results are: (i) The in-phase component of the

current with ac was due to field emission, (ii) The emission current with ac,

for given gap spacing and voltage, was two or three orders more than that with

direct voltage, and (iii) The Fowler-Nordheim [1] plot (F-N plot) with ac showed a bend towards a higher field intensification factor whereas the F-N

plot with dc was a straight line. This shows that the emission current with

ac cannot simply be explained by the Fowler-Nordheim theory alone. The effect

of space charge, desorption of gases and lowering of work function of the

electrode material may be responsible for the bend, (iv) The value of field

intensification factor was two or three times more than that with the direct

voltage for any gap spacing.

An examination of the electrode surface after multiple breakdowns with ac

and dc gave some interesting results. The patchy areas on the anode surface

contained a large number of shallow craters with smooth, round rims. The

Figures in square brackets indicate the publication reference at the end of this

project review.

110
cathode , on the other hand , had craters which appeared to be deeper with irregular lips with tear-like globules, possibly due to melting of metal. Thus the

damage on the cathode was distinctly different from that of anode. With ac,

both electrodes had identical damage, similar to that of the anode in the

dc case. This could mean that in clean gap the breakdown mechanism with ac is

the mechanism responsible for the anode damage with dc.

It is seen that the prebreakdown phenomena in clean gap with ac has some

significant differences compared with dc. In particular the increased emission

current and increased value of the field itensification factor seem to have a

direct bearing on lowering the breakdown voltage across solid dielectrics in

vacuum with ac.

The NBS monitor states that from his viewpoint the Indian work represents a significant contribution toward meeting the need felt by the High Voltage Measurements Section

staff for an improved understanding of the phenomena associated with electrical breakdown

in their efforts to design more compact and reliable facilities for high voltage measurements research and to respond more effectively as consultants to others involved in the

design of equipment requiring high voltage insulation.

References

1. R. H. Fowler and L. W. Nordheim, "Fowler-Nordheim Plot," Proc. Roy. Soc. , A 119,

173 (1928).

List of Publications that Resulted from the Project

1. G. R. Nagabhushana , G. Parthasarathy , and H. V. Gopalakrishna , "A Generalized Theory

of Direct Voltage Breakdown Across Solid Dielectrics in Vacuum," Proceedings of the

IVth International Symposium on Discharges and Electrical Insulation in Vacuum,

Waterloo (1970).

2. G. Parthasarathy and H. V. Gopalakrishna, "Prebreakdown Phenomenon in Vacuum Gaps

Subject to Alternating Voltages," Proceedings of the IVth International Symposium

on Discharges and Electrical Insulation in Vacuum, Waterloo 5 214 (1970).

3. G. R. Nagabhushana, G. Parthasarathy, and H. V. Gopalakrishna , "Director Voltage

Breakdown Across Solid Dielectrics in Vacuum: Effects of Conditioning of Specimen

and Electrodes," 2nd Conference on High Voltage Insulation in Vacuum, Institution

111
of Electrical Engineering, London, 68 (1971).

4. G. Parthasarathy and H. V. Gopalakrishna , "Breakdown Over Solid Dielectrics in High

Vacuum at Power Frequency Voltages," Proceedings of the Vth International Symposium

on Discharges and Electrical Insulation in Vacuum, Poland, 321 (1972).

5. G. R. Nagabhushana and H. V. Gopalakrishna, "Methods of Improving the Breakdown

Voltage Over Solid Dielectrics in Vacuum," Proceedings of the Vth International

Symposium on Discharges and Electrical Insulation in Vacuum, Poland, 339 (1972).

112
B.ll.» NUCLEAR AND RADIATION TECHNOLOGY

Project Title : EXPERIMENTAL INVESTIGATIONS ON THE GENERALIZED OPTICAL MODEL PARAMETERS

OF FAST NEUTRONS

Principal Investigator : Professor A. M. Ghose

Institution : Bose Institute, Calcutta

NBS Monitor : Dr. Robert B. Schwartz

NBS Institute or Center and Division : Institute for Basic Standards

Nuclear Radiation Division

Summary Description of Project Goals

The nucleus is a very complicated many-body system of particles and at the present

state of our knowledge, there is no easy way following which the basic properties of nuclei

can be derived logically from the known interaction processes between any two nucleons. We

are, therefore, forced to develop semi-empirical models which are valid for certain regions

of energy. The optical model is one of the most successful models of nuclear reactions for

moderate energy neutrons interacting with nuclei which are not too light. Apart from its

'theoretical utility, the model is extremely useful in the design of radiation shielding for

fast particles and other fields of practical importance. The object of the present project

is to measure fast neutron nuclear reaction and scattering cross sections accurately, so

that the values of the empirical parameters occurring in the optical model can be determined

precisely. The polarization measurements will directly yield the values of the spin-orbit

interactions, which are not sensitive at all to other methds of investigations.

The experimental program will consist of measurements of the total elastic and nonelastic cross sections , and differential elastic cross sections , for the interaction of

fast neutrons with nuclei. In addition, polarization during elastic scattering, and the

cross sections for formation of some excited states may be measured. These data will be

used to determine optical model parameters , and to study their variation with mass number

and energy.

Results and Implications to Date

(1) Measurement of nonelastic cross sections

Nonelastic cross section of neutrons at 14.2 and 14.8 MeV have been measured for

several nuclei of low, medium, and high atomic number elements. The modified sphere

" The alphanumeric designation refers to the NBS Program Structure (see Appendix II).

113
transmission technique developed in this Laboratory has been employed for the

measurement of the nonelastic cross sections . The transmission data have been

corrected for multiple scattering and for energy loss by elastic collision. The

first correction has been obtained by using the polynomial extrapolation method, a

detailed theoretical justification for which has already been given by us [1] .

The second correction has been obtained by the two-bias method developed in this

Laboratory [2]. In effect, we have developed a neutron counting method in which

all elastic neutrons are detected with equal efficiency while the inelastic ones

are completely cut off.

The measured nonelastic cross sections have been compared with the cross section

values calculated on the basis of existing local and nonlocal optical model calculations. The present experimental data cannot be fitted to either of the two sets of

calculated values. This comparison enforces the justification for a reevaluation of

the optical model parameters. To make this calculation successful we need very many

cross section measurements for different nuclei and different neutron energies. For

this purpose a plan is being worked out with the Department of Atomic Energy, Government of India, to carry out measurements at different energies using accelerators

available at Trombay.

(2) Measurement of Absolute (n,2n) cross sections

Absolute (n,2n) reaction cross sections of several nuclei have been measured at

three different neutron energies - 14.2, 14-. 5, and 14.8 MeV. The absolute neutron

flux has been measured within ± 3 percent by using a heavily biased plastic scintillation detector and using the theory of the response of organic scintillators to fast

neutrons as developed by us [ 3 ] . The absolute activity of the irradiated samples has

been measured using a coincidence spectrometer. The spectrometer was calibrated

22 within ± 2 % by using a standard Na source obtained from NBS. The measured cross

sections have error limits ranging from 5 to 10 I.

The literature cross section values show some large difference in the measured

values. This is probably due to the inaccuracies in the measurement of the activity

of the irradiated samples. We have tried to minimize this by taking into account one

Figures in square brackets indicate the publication reference at the end of this

project review.

114
important source of error which is often overlooked in this field, namely, the error

arising from the finite dimensions of the irradiated targets. We have also observed

that measured cross section values when plotted against the asymmetry parameter show

no shell structure effect.

The NBS monitor states that from his viewpoint the Indian work will provide important

data for a proposed neutron dosimetry standards program within NBS. Both the cross sections

which are explicitly measured under this project, and the improved optical model calculations which may result from these data may contribute significantly to the program of NBS.

References

1. A. M. Ghose, Nucl. Instr. and Methods 35_, 45 (1965).

2. A. Chatterjee and A. M. Ghose, Phys. Rev. 161, 1181 (1967).

3. A. Chatterjee and A. M. Ghose, Trans. Bose Institute, 29_, 2 (1966).

List of Publications that Resulted from the Project

This is a new project and so far only one paper has been presented:

B. Pal, A. Chatterjee, and A. M. Ghose, Proc. Nucl. Phys. £ Solid State Physics Symp.

14B, 33 (1972).

115
B.ll." NUCLEAR AND RADIATION TECHNOLOGY

Project Title : INVESTIGATIONS ON THE INTERACTION OF GAMMA RAYS WITH MATTER

Principal Investigator : Dr. A. M. Ghose

Institution : Bose Institute, Calcutta

NBS Monitors : Dr. E. G. Fuller (1966-1969)

Mr. J. H. Hubbell (1970 on)

NBS Institute or Center and Division : Institute for Basic Standards

Center for Radiation Research

Summary Description of Project Goals

The aim of the project was to investigate some of the fundamental interactions of gamma

rays with matter. The specific areas which were proposed to be investigated included the

measurement of photoelectric cross-sections, coherent and non-coherent scattering phenomena,

pair production phenomena etc. Development of new experimental techniques and specialized

instruments formed an integral part of these investigations. The results obtained were

proposed to be utilized for a better understanding of interaction processes of radiation

with matter and for probing the electronic structure of the heavier atoms.

Results and Implications to Date

A scintillation counter was developed which had constant efficiency over the photon

range .25 to 1.5 MeV. This counter consisted of a Tl doped Nal crystal with a perforated

Al filter.

A scintillation detector was developed which divided the light output from a single

Nal(Tl) crystal between two photo-multipliers (by means of a perforated reflecting Al foil

mounted at 45 ) and then took coincidence counts.

Using the sphere transmission method described in the first paper arising from this

project, the investigator measured the atomic photoeffect cross section for 1.17 and

1.33 MeV gamma rays (from Co ) in Hg and Pb. In Pb the cross section was also measured

using .662 MeV (Cs

137

) and .835 MeV (Mn

54

) gamma rays.

14-1 The coherent scattering cross sections for .145 MeV gamma rays (Ce ) by atoms of

C, Al, Fe, Cu, Sn, and Pb were measured over the angular range 2.67 to 25.40 . The

coherent scattering cross section of 1.33 MeV (Co ) gamma rays by Pb were measured over the

range 10 to 25 . These results were compared to form-factor calculations based on the

" The alphanumeric designation refers to the NBS Program Structure (see Appendix II).

116
Thomas-Fermi and Hartree-Fock approximations . Agreement was better when the Hartree-Fock

approximation was used.

Coherent scattering cross sections of gamma rays are best known in the non-relativistic

region. In the relativistic region, the values of this important parameter have been calculated , with great difficulty , for only a few isolated cases . To overcome this difficult*

an empirical formula was developed for estimating coherent scattering cross sections of

X-rays of energies below 1.5 MeV and in the range of 0- 2.5 mc units of momentum transfer.

The formula was compared with the experimental data available in the literature for Pb, Sn,

and Cu scatterers for different photon energies between 0.279 and 1.33 MeV. Experimental

data, in general, were found to be in good agreement with the results of the empirical

formula, the deviation being within ± 10% in most cases. The empirical formula was also

compared with the form factor results of Nelms and Oppenheim [1] and with the predictions

of Brown and Mayers [2]. The latter were in excellent agreement with the empirical formula.

The empirical formula obtained was of the form:

a (6) = \ (T + Cos

29) <KE,q) (| 2

) "(q) fp

(q)

where cf> (E ,q) , n(q) , and f (q) were relatively simple algebraic expressions for the parameters involved.

Although approximate theoretical estimates of electronic charge distribution in atoms

have been reported in the literature, to our knowledge, no study of these distributions

based mainly on experimental results has yet been reported for heavy elements. In fact

above Z = 10, X-ray techniques cannot resolve K and L shells. We therefore undertook the

present work with a view to determine the electronic charge distribution for heavy elements

using the experimentally measured coherent scattering cross section data. The present

method for determining the value of electronic charge distribution involves the determination of the atomic form factor F(q,Z) for a wide range of momentum transfer q from the

experimental values of coherent cross sections and to carry out the numerical integration

over q using the usual formula „

P(r) = 2u

2r h

2

j

- F(Z ' q) Sin

IT

q-dq

c

Figures in square brackets indicate the publication reference at the end of this

project review.

117
where P(r) is the electronic charge density at a distance r from the center of the atom.

We have calculated the electronic charge distribution for lead. The comparison of the

result thus obtained with the Hartree-Fock self-consistent field model shows reasonably

good agreement except close to the nucleus. Therefore we may conclude that the present

method for determining the electronic charge density distribution is feasible although to

compare theoretical and experimental distributions more accurate experimental measurements

on the coherent scattering cross sections for high momentum transfers are essential.

In addition to closely related experimental programs at NBS such as the K-shell Compton

scattering measurements of Dr. J. W. Motz, NBS is a critical consumer of such data in its

program of radiation transport calculations by M.J. Berger and others in the Radiation

Theory Section. Also, NBS has since 1952 continued a program of collection, evaluation,

and compilation of data on gamma-ray interactions with matter, and at present the OSRD

supports this activity within the Radiation Theory Section in the form of an "X-ray

Attenuation Coefficient Information Center" under the present direction of Mr. J.H.Hubbell.

The monitor states that from his viewpoint the Indian work is a useful adjunct to gammaray interaction studies carried out in the US and elsewhere. In the context of the NBS

x-ray data compilation project, the Bose Institute experimental results have in some cases

filled gaps in the available data, and in others have provided useful independent data to

combine with measurements taken elsewhere. However, the value of some of the associated

theoretical analysis , such as the empirical formulas for coherent scattering and K-shell

photoeffect may be somewhat short-lived as a result of extensive new all-Z calculations

of coherent and incoherent scattering functions (0.1.95 mc units of momentum transfer) by

D. Cromer (Los Alamos) and photoeffect (1 keV-1 MeV, total and all subshells including

K-shell) by J. Scofield (Livermore)

.

References :

1. A. J. Nelms and I. Oppenheim, J. Res. NBS, 55_, 53 (1955).

2. G. E. Brown and D. F. Mayers, Froc. Roy. Soc. , London, A242, 89 (1957).

List of Publications that Resulted from the Project

1. A. M. Giose, Nucl. Instr. and Meth. , 35_, 45-54 (1965)."

2. A. Nath, Tras. Bose Res. Inst., 29, No. 2, 51-83 (1966).

•c Although publication of this paper procedes the final signing of the grant, the work

was carried out in anticipation of its activation.

118
3. A. Nath and A. M. Ghose, Nucl. Phys. £ Solid State Phys., (India),

260-264 (1966).

4. A. M. Ghose, Nucl. Phys. £ Solid State Phys., (India), 10A , 85 (1968).

5. A. Nath and A. M. Ghose, Nucl. Phys. £ Solid State Phys. (India),

9A, 519 (1967).

6. A. Nath and A. M. Ghose, NBS Technical Note 442 (1968).

7. S. C. Roy, A. Chatterjee, and A. M. Ghose, Nucl. Phys. 8 Solid State Phys.

(India), 11B, 193-197 (1968).

8. S. C. Roy, A. Chatterjee, and A. M. Ghose, Nucl. Instr. £ Methods 67_, 318-322 (1969),

9. S. C. Roy and A. M. Ghose, Nucl. Phys. £ Solid State Phys. ,( India)

, 12B

65-69 (1969).

10. A. Nath, Nucl. Phys. £ Solid State Phys., (India), 12B, 76-80 (1969).

11. M. Biswas, S. C. Roy, and A. M. Ghose, Nucl. Phys. £ Solid State Phys., (India),

s 13B, 183-186 (1970).

12. S. C. Roy and A. M. Ghose, Nucl. Phys. £ Solid State Phys., (India), 13C ,

121-124 (1970).

13. M. Biswas, S. C. Roy, and A. M. Ghose, Nucl. Phys. £ Solid State Phys., (India),

13B , 483-486 (1970).

14. S. C. Roy and A. M. Ghose, Nucl. Phys. £ Solid State Phys., (India), 14C, 79 (1971).

119
B.ll." NUCLEAR AND RADIATION TECHNOLOGY

Project Title : GAMMA RAY SCATTERING, PART I.

Principal Investigator : Professor P. P. Kane

Institution : Indian Institute of Technology , Bombay

NBS Monitor : Dr. J. W. Motz

NBS Institute or Center and Division : Institute for Basic Standards

Applied Radiation Division

Summary Description of Project Goals

The elastic scattering of 1.12 MeV and 1.33 MeV gamma rays by electrons bound to

eight different types of atoms (ranging in atomic number from copper to lead) was to be

studied. Differential cross sections for scattering angles between 90 and 124.5 were

to be measured.

The Compton scattering of 1.12 MeV gamma rays from electrons bound to heavy elements

was to be studied for a number of different scattering angles.

Results and Implications to Date

The elastic scattering differential cross-sections mentioned were measured and reported

in the various papers mentioned at the end of this report. The results may indicate a dispersive Delhriick scattering amplitude at 124.5 ; further investigations on this point are to

be carried out under a subsequent contract.

The Compton scattering measurements were made at 60 , 90 , and 120 ; some measurements

were also made at 25 . A byproduct of this work was a review article, entitled "Possibilities of Observation

of Nonlinear Quantum Electrodynamic Effects in Vacuum," published in Reviews of Modern

Physics.

List of Publications that Resulted from the Project

1. P. P. Kane and G. Basavaraju, "Elastic Scattering of 1.33 MeV Gamma Rays at High

Momentum Transfer as a Function of Atomic Number," Proc. Nuclear and Solid State Physics

Symposium, Kanpur, 9A, 507-512 (1967). (Dept. of Atomic Energy, Government of India,

Publishers )

.

2. P.P. Kane, "Real Part of the Delhruck Scattering Amplitude and its Experimental

" The alphanumeric designation refers to the NBS Program Structure (see Appendix II).

120
Verification at 124.5°," ibid, 513 (1967).

3. P. P. Kane and G. Basavaraju, "Possibilities of Observation of Non-linear Quantum

Electrodynamic Effects in Vacuum," Rev. Mod. Phys. , 39_, 52-58 (1967).

4. P. P. Kane, Paper "Recent Work and Immediate Prospects in X-Ray and Gamma Scattering,"

Proc. Nuclear and Solid State Physics Symposium, Bombay, 11A , 87-105 (1968). (Dept. of

Atomic Energy , Government of India , publishers )

.

5. P. P. Kane and P. N. Baba Prasad, "Compton Scattering by K-shell Electrons at 1.12 MeVI," Proc. Nuclear and Solid State Physics Symposium, Roorkee, 12B_, 81-83 (1969).

(Dept. of Atomic Energy, Government of India, publishers).

6. P. P. Kane and P. N. Baba Prasad, "Compton Scattering by K-shell Electrons at 1.12 KeVII," Proc. Nuclear and Solid State Physics, Madurai, 13B, 187-191 (1970). (Dept. of

Atomic Energy, Government of India, publishers).

121
B.ll.* NUCLEAR AND RADIATION TECHNOLOGY

Project Title : GAMMA RAY SCATTERING, PART II.

Principal Investigator : Professor P. P. Kane

Institution : Indian Institute of Technology, Bombay

NBS Monitor : Mr. John H. Hubbell

NBS Institute or Center and Division : Institute for Basic Standards

Center for Radiation Research

Summary Description of Project Goals

The objective was to carry out a study of elastic and Compton scattering of 1.12 MeV

and 1.33 MeV gamma rays by atomic electrons.

Results and Implications to Date

The desired measurements were made, using sodium iodide counters. The results were

compared to theoretical predictions and the apparent implications regarding the real

Delbruck scattering term were given in some detail in the 1970 Nuclear Physics paper.

Studies done up to now were carried out using a sodium iodide counter with a resolution

of only six to seven percent at the experimental energies . It is intended to acquire a

lithium drifted germanium counter with a resolution of about three tenths of one percent,

and to carry our further experiments varying the photon energy, angular range, and target

materials ; the choice of ranges and materials will be made in the light of the results

obtained. The results will be compared with theoretical predictions as before.

List of Publications that Resulted from the Project

I

1. P. P. Kane and G. Basavaraju, "Elastic Scattering of 1.12 MeV and 1.33 MeV Gamma

Rays Through 90° and 124. 5° by Different Elements and tb

Scattering Amplitudes," Nuclear Phys. A149, 49-62 (1970)

Rays Through 90° and 124.5° by Different Elements and the Real Parts of the Delbruck

The alphanumeric designation refers to the NBS Program Structure (see Appendix II)

122
APPENDIX I

SFCP (PL 480) BACKGROUND HISTORY

Since the Fiscal Year (FY) 1961 the National Bureau of Standards has had an active

Special Foreign Currency Program (SFCP) in India, Israel, and Pakistan. During 1970,

Yugoslavia was added to the list of countries and Poland and the Arab Republic of Egypt in

1972.

The relevant US laws , such as PL-480 of the 83rd Congress pertaining to the use of

SFCP funds , callenge imaginative implementation at the same time as they offer the opportunity for international collaboration to universal benefit. In the mission area of NBS and

with the available countries, Dr. Lewis M. Branscomb, former Director of NBS, had called

for an effective program. To this end, Mr. H. Steffen Peiser, as program manager, under

the supervision of Dr. E. L. Brady, Associate Director for Information Programs, has

received wide-ranging support, which is hereby gratefully acknowledged.

Stated Policy for NBS /SFCP Grants

NBS/SFCP grants provide supplementary resources that provide an appropriate means for

accomplishing NBS objectives, consistent with U.S. foreign policy objectives. NBS criteria

for this purpose are:

"1. All projects must be of scientific or technological excellence.

2. All projects must be within the mainstream of NBS interests or contribute

directly to NBS effectiveness.

3. All projects must benefit both the U.S. and the participating countries:

(a) NBS/SFCP funds must not merely replace otherwise available country

funds ; and

(b) Individuals or institutions abroad must not become primarily dependent

upon NBS for long term support.

M-. All projects must be followed closely by NBS staff members working in related

areas . Thus , one or more NBS staff should maintain a continuing direct relationship with the foreign person or group. This relationship should be strengthened

by visits in either or both directions.

123
5. NBS involvement with a technical institution of another nation should be consistent

with U.S. foreign policy. For example, relationships with sister institutions,

staff exchanges, and visits should be carried on in the context of overall U.S.

objectives in its relationship with the other country.

6. NBS staff travel to participating foreign countries should be exploited, when

practical, by suitable additional itinerary to identify additional targets for

bilateral benefit or to provide additional strength to existing relationships.

Such travel should be coordinated with the NBS/SFCP Manager."

Bureau Level Management

Mr. H. Steffen Peiser has been designated the NBS/SFCP Manager by the Director.

As such he has the following responsibilities and authorities

:

"1. Makes final decisions on grant proposals, allocates funds, and signs SFCP

documents

.

2. Serves as the principal point of contact with:

a. The Director on NBS/SFCP policy,

b. The Institutes and Centers on specific proposals and program planning,

c. The Budget Division on all budget related matters,

d. The Procurement Section on grant execution and administrative matters,

e. The Office of International Relations on matters of channelling

communications and relations with the Department of State.

3. Authorizes all foreign travel related to the activated or potential NBS/SFCP

grants .

Institute Level Management

Each major organizational unit has the following responsibilities:

"1. Technically evaluates proposals and determines whether the proposals

meet Criteria 1, 2 and 4 of the SFCP policy statement for support

under the program.

2. Recommends proposals to the SFCP Manager for support and makes priorities

known to him.

3. Assures that there is continuing involvement by the designated monitor

once a grant has been let.

4. Advises and assists the SFCP Manager in formulating program plans and

budget requests .

124
APPENDIX II

NBS PROGRAM STRUCTURE

A. Promoting Accurate, Meaningful and Compatible Scientific and Technical Measurements

1. Physical Measurement Methods, Units and Standards

2. Measurement Transfer Services

3. Time and Frequency Dissemination Services

4. (Not used)

5. Standard Reference Data

6. Standard Reference Materials

7. (Not used)

8. Materials Measurement Methods and Standards

9. Properties of Matter

10. Exploratory Research

B. Promoting More Effective Use of Science and Technology

1. Materials Science and Technology

a. Metallurgical Materials

b. Polymeric Materials

c. Inorganic Materials

d. Composite Materials

e. Dental Materials

f

.

Chemical Materials

2. Environmental Pollution Measurement Methods and Standards

3

5

6

7

8

9

10

a. Air

b

.

Water

c. (Not used)

d

.

Noise

e

.

Electromagnetic

Building Technology

Computer Science and Technology

Analysis of Technical Systems

Electronic Technology

Cryogenic Technology

Technology Utilization Analysis

Failure Avoidance

(Not used)

125
11. Nuclear and Radiation Technology

12. Illumination Technology

C. Promoting Strength in the Economy and Equity for Buyer and Seller in Trade

1. Voluntary Engineering Standards

2. Measures of Quantities Important to Commerce

3. Product Performance

4. Testing Laboratory Evaluation

5. Fair Packaging and Labeling

D. Standards and Test Methods for Protection of the Public from Specified Hazards

1. Fire Research

a. Flammable Fabrics

b. Fire Research and Safety

2. Radiation Safety

a. Radioactivity

b. X-rays and Other Ionizing Radiation

c. Microwave Radiation

d. Laser Radiation

e. Ultrasonic Radiation

3. Product Safety

126
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APPENDIX IV ALPHABETIC LIST OF NBS MONITORS

NBS Monitor Division Page(s)

Bass, A. Bates, R. G. Bennett, H. S. Block, S. Caswell, R. S. Coyle, T. D. Durst, R. A. Fuller, E. G. Gevantman, L. H. Heydemann, P.L.M. Horton, W. S. Hubbell, J. H. Kahan, D. Kahn, A. Klein, R. Kotter, F. R. McMurdie, H.F. Menis, 0. Michaelis, R. E. Motz, J. W. Peiser, H. S. Pfrang, E. 0. Roth, R. S. Scheer, M. D. Schwartz, R. B. Taylor, J. K. Wachtman, J. B. White, H. J.

316

310

310

313

240

313

310

241

151

221

313

240

312

313

316

211

313

310

302

243

156

460

313

316

240

310

313

151

34, 51

98260

46

77

9116

18, 24, 26, 30

770

116, 122

19

9563, 64 107

27

58

55120

27102, 105

82

5113

982

21

130
APPENDIX V

ALPHABETIC LIST OF PRINCIPAL INVESTIGATORS

University, Institute, or "Laboratory Page ( s

)

National Metallurgical Laboratory (Jamshedpur) 55 National Metallurgical Laboratory (Jamshedpur) 55 National Chemical Laboratory (Poona) 70

Jadavpur University (Calcutta) 9 Bose Institute (Calcutta) 113 ,116 ITT (Bangalore) 107 IIT (Mew Delhi) 18

Roorkee University (Roorkee) 19 IIT (Kanpur) 105

IIT (Bombay) 120 , 123 IIT (Madras) 77 Allahabad University (Allahabad) 5 IISc ( Bangalore ) 7 IIT (Kanpur) 21 Central Glass S Ceramic Research

Institute (Calcutta) 58 Jadavpur University (Calcutta) 9 IIT (Madras) 63 IISc (Bangalore) 7 IIT (Kanpur) 24, 26, 27 IIT (Kanpur) 51 IIT (Kanpur) 30 IIT (Kanpur) 102

Osmania University (Hyderabad) 60 IIT (Madras) 64 IIT (Madras) 63 Banaras Hindu University (Varanasi) 34 IIT (Madras) 64 IIT (Kanpur) 82 IIT (Kanpur) 105

Panjab University (Chandigarh) 46 IIT (Kanpur) 51

University of Allahabad (Allahabad) 95

Principal Investigator

Altekar, V. A. Bhattacharya, H. P. Dadape, V. V. Das. M. N. Ghose, A. M. Gopalakrishna, H. Jain , S . C

.

Joshi, S. K. Kadambi, V. Kane, P. P. Khan, M. M. Taqui

Kor, S. K. Krishnan, R. S. Kudchadker, A. P. Kumar , S

.

Kundu, K. K. Pillai, C. N. Rajagopal, E. S. Rao, C. N. R. Rao, D. Ramachandra

Rao, G. N. Rao, J. K. Sridhar

Rao, K. V. Krishna

Sastri, M. V. C. Satyanarayana , M. Singh, N. L. Srinivasan, V. Subbarao, E. C. Sundararaj an , V. Trehan, P. N. Venkateswarlu , V. Verma, G. S.

131
APPENDIX VI

INDEX OF INSTITUTES

Institute, Laboratory or University Page ( s

)

Allahabad University , Allahabad 5,95

Banaras Hindu University , Varanasi 34

Bose Institute , Calcutta 113 , 116

Central Glass £ Ceramic Institute, Calcutta 58

Indian Institute of Science, Bangalore 7 , 107

Indian Institute of Technology , Bombay 120

Indian Institute of Technology, Kanpur 21, 24, 26, 27, 30, 51, 82, 102, 105

Indian Institute of Technology, Madras 63 , 64, 77

Indian Institute of Technology , New Delhi 18

Jadavpur University , Jadavpur 9

National Chemical Research Laboratory 70

National Metallurgical Laboratory, Jamshedpur 55

Osmania University , Hyderabad 60

Panjab University , Chandigarh 46

Roorkee University , Roorkee 19

* U. S. GOVERNMENT PRINTING OFFICE : 1 973--542-650/72

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Collaborative Research Program Between NBS and Indian

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