bluuebunny/crossref_metadata_2025 huggingface dataset:
Vibration Spectrum of Graphite and Boron Nitride. I. The Two-Dimensional Spectrum
Authors: Newell Gordon F.
Published: January 2005

A detailed analysis of the vibrational modes of graphite and boron nitride, which are sufficiently similar that they can conveniently be considered together, begins here with a study of the effects of interactions only between particles in the same layers of the lamellar structure.

The secular equation for any lattice vibration problem can be written as a sum of contributions arising from the interactions between various groups of particles. After describing a system of notation which will eventually be used to describe all types of interactions, that part of the secular equation resulting only from nearest neighbors is derived. The frequencies and the spectral densities of all frequency branches are obtained for a system with only these forces. Because of the existence of some low-frequency branches, it is necessary to also consider second nearest neighbor forces, even though they may be relatively much weaker, in order to obtain a complete realistic description. The frequencies of all modes of the system with both types of forces are then analyzed. Part of the spectrum can still be found in closed form; other parts can be found only approximately.

This analysis gives a fairly complete description of a ``coarse grain'' frequency distribution which can, in principle, be used to describe the thermodynamic behavior of the system at all but the lowest temperatures where the interactions between layers become significant. The principle limitation on its usefulness is at present due to the sizable number of as yet unknown parameters necessary to describe the system numerically.
Molecular Rotation and Translation in Crystals. Nuclear Magnetic Resonance Absorption, Heat Capacity, and Entropy of Crystalline Solid Solutions of 2,2-Dimethylbutane in 2,3-Dimethylbutane from 10°K to 273°K
Authors: Aston John G. , Segall H. , Fuschillo N.
Published: January 2005

The nuclear magnetic resonance absorption of solid solutions of 2,2-dimethylbutane (A) and 2,3-dimethylbutane (B) has been studied as a function of composition. The melting range is clearly marked, but the rotational transition is absent. There is a maximum in the melting point diagram at the composition B2 A3. Thermal data have been determined on this complex from 10°K to 265°K from which the zero-point entropy has been deduced. The heat capacity curve and zero-point entropy of the crystals are those of a glass which indicates translational freedom in the rotating crystals.
Debye Characteristic Temperature at 0°K of Certain Cubic Crystals
Authors: de Launay Jules
Published: January 2005

In an earlier article the author presented a numerical table which permits an easy calculation of the Debye characteristic temperature at 0°K for cubic metallic elements whose elastic constants exhibit the inequality c12>c44. This table has been extended to include some cubic nonmetallic elements whose elastic constants exhibit the inequality c12<c44. The new table has been utilized in the calculation of the characteristic temperatures of diamond, Ge, and Si from their elastic constants.
Detonation of Nitromethane
Authors: Nahmani G. , Manheimer Y.
Published: January 2005

The detonation velocity of nitromethane has been measured for various charge radii and confining materials. A critical diameter of 27 mm for the detonation of unconfined nitromethane has been found. Estimates of the energy of activation, the length of the reaction zone and the reaction time are obtained, according to Eyring's theory.
Nuclear Quadrupole Levels in Single Crystals
Authors: Parker Paul M.
Published: January 2005

Numerical methods are used to study the behavior of the energy levels of a nucleus, having nonzero quadrupole moment and spin I = 1 or 32, under the influence of a constant uniform external magnetic field and an electric crystalline field of axial symmetry. These numerical results are of use when experimental conditions are such that perturbation theory cannot be applied in data analysis.
Electrostatic Free Energy and Other Properties of States Having Nonequilibrium Polarization. I
Authors: Marcus R. A.
Published: January 2005

Various processes such as electron transfer reactions, redox reactions at electrodes, and electronic excitation of dissolved ions may proceed by way of intermediate states whose electrical polarization is not in equilibrium with the field arising from the charges present. The usual expressions for the electrostatic free energy and for the differential equation satisfied by the potential assume that the polarization and the field are in equilibrium. Accordingly, these equations are of but limited applicability to these processes. In the present paper equations are derived for various properties of systems having such nonequilibrium electrostatic configurations. These properties include the free energy, energy, and entropy of the nonequilibrium system, and the spacial dependence of the electrostatic potential. The free energy, for example, will be used to calculate the probability of formation of nonequilibrium states in certain problems of physical interest.
Vibration—Rotation Interaction in Polyatomic Molecules. II. The Determination of Coriolis Coupling Coefficients
Authors: Meal Janet Hawkins , Polo S. R.
Published: January 2005

A general method for the analytical treatment of vibration-rotation interaction in polyatomic molecules is presented. The method is especially adapted to carry out the calculation of the Coriolis coupling coefficients along with the normal coordinate treatment in terms of any chosen set of internal coordinates. The relations existing among the ζ elements and the potential constants are established in a general and convenient form. Particular attention is given to symmetric top molecules, and the effect of vibration-rotation interaction on band structure is discussed. Approximate methods for the calculation of zeta values are considered also.
On the Pi-Electron Approximation and Its Possible Refinement
Authors: Lykos Peter G. , Parr Robert G.
Published: January 2005

The pi-electron approximation is defined to be the approximation in which the following two restrictions are imposed upon the total approximate electronic wave functions for some group of molecular states:

(I) The wave function for each state satisfies the sigma-pi separability conditions: (A) the wave function has the form Ψ = [(Σ) (II)], where (Σ) and (II) are antisymmetrized functions describing the so-called sigma and pi electrons, respectively, and the outer brackets connote antisymmetrization with respect to sigma-pi exchange; (B) each of (Σ), (II), and Ψ is normalized to unity; (C) each of (Σ), (II), and Ψ is well-behaved.

(II) The sigma description is the same for all states.

Imposition of these restrictions is shown to be sufficient to validate the customary procedure in which the pi electrons in a molecule are treated apart from the rest.

A formula is given for the pi-electron Hamiltonian to be used when the pi-electron approximation is invoked. Present day pi-electron theories are examined, and lines for carrying out improved calculations are suggested. An iterative procedure is proposed for treating both sigma and pi electrons wherein first a sigma function is assumed (which defines a ``core'' in the field of which the pi electrons move), then a pi function is computed (which defines a ``peel'' in the field of which the sigma electrons move), then a new sigma function is computed, and so on.

Certain generalizations of the quantum-mechanical argument are made which give it wider applicability, and several illustrations are drawn from pi-electron theory and elsewhere.
Temperature Dependence of the Viscosity of Liquids
Authors: Hellund E. J.
Published: January 2005

The consequences of the introduction of long-range disorder into the theory of the liquid state are examined. Application is made to the analysis of viscosity.
9.6-Micron Band of Telluric Ozone and Its Rotational Analysis
Authors: Kaplan L. D. , Migeotte M. V. , Neven L.
Published: January 2005

The 9.6-micron band of atmospheric ozone has been investigated by means of high resolution measurements of the solar spectrum from the Jungfraujoch in Switzerland. A rotational analysis confirms its assignment as the v3 fundamental and results in the following values for the vibrational frequency and rotational constants: ν3=1042.16 cm−1;  A=3.502 cm−1,  B=0.4401 cm−1,  C=0.3883 cm−1.

The decrease of all three rotational constants relative to the ground-state values suggests an appreciable Coriolis interaction with the v1 fundamental.
Spectra and Quantum States of the Europic Ion in Crystals. II. Fluorescence and Absorption Spectra of Single Crystals of Europic Ethylsulfate Nonahydrate
Authors: Sayre Edward V. , Freed Simon
Published: January 2005

From the polarization properties of the fluorescence spectrum of single crystals of europic ethylsulfate nonahydrate it was possible to determine the multipole character of transitions, the energies and quantum nature of the seven levels of the ground state multiplet of the europic ion, and the group character of the sublevels into which these states are split by the crystal field. Such an analysis was made of all pure, uncoupled electronic transitions in the fluorescence spectrum. The analysis revealed that the rare earth ion is predominantly perturbed by a field of D3h symmetry, arising from the water molecules of hydration immediately surrounding it. Upon this field is superimposed a weaker one of lower symmetry, C3h, arising from the lattice as a whole. All transitions involving a change of J of one appeared as magnetic dipole radiation. All others appeared as forced electric dipole transitions, including one which would have been fully allowed as a magnetic dipole transition.

A similar analysis of the absorption spectrum in the near ultraviolet was only partially successful because of the superposition of the split levels of some of the upper states. It was in accord with the analysis of the fluorescence spectrum and from it was determined the multipole nature of the transitions and the quantum nature of some of the more isolated upper states.
``Donor-Acceptor'' Complex Formation by High Polymers
Authors: Evans D. F.
Published: January 2005

The interaction of iodine with polystyrene and rubber has been studied spectrophotometrically. Characteristic ``charge-transfer'' bands were observed, and interpreted quantitatively in terms of complex formation. The equilibrium constants and ``molar'' extinction coefficients of the polymer-iodine complexes are similar to those for the iodine complexes of analogous simple aromatic and olefinic molecules. Approximately half of the iodine in solid solution in polystyrene seems to be involved in complex formation. Polystyrene is soluble in strong alcoholic solutions of silver perchlorate, and the absorption spectrum of the solution indicates complex formation.
Infrared Spectra and Molecular Constants of Gaseous Tritium Bromide and Tritium Chloride
Authors: Jones Llewellyn H. , Robinson Eugene S.
Published: January 2005

The infrared spectra of TCl35, TCl37, and TBr79,81 have been observed using a CaF2 prism. Throughout this paper the notation TBr79,81 indicates the natural isotopic mixture of Br79 and Br81, and lack of spectral resolution of the two isotopes. A least squares treatment of the data yielded the following molecular constants for TBr79,81, TCl35, and TCl37, respectively: ν0=1519.26,          1739.10,          1735.51 cm−1Be=  2.899,            3.746,            3.723 cm−1αe=  0.046,            0.061,            0.066 cm−1De=  4.5×10−5        7.7×10−5         6.8×10−5 cm−1
Use of f Orbitals in Covalent Bonding
Authors: Eisenstein J. C.
Published: January 2005

The hybridization of atomic orbitals is considered from a group theoretical point of view. The earlier work of Kimball is extended to include atomic f-orbitals in the hybrids. By use of the tables presented it is possible to tell at a glance what atomic orbitals can be combined to form bonding orbitals for a number of different spatial arrangements of the bonds. The strength of the hybrids is calculated for a few particularly symmetrical arrangements. Finally, the complexes (UO2)++, UCl6, and UCl4 are discussed and it is argued that f-orbitals on the uranium atoms are used for covalent bonding.
Microwave Spectra, Dipole Moment, and Barrier to Internal Rotation of CH3NO2 and CD3NO2
Authors: Tannenbaum Eileen , Myers Rollie J. , Gwinn William D.
Published: January 2005

The J = 1 to J = 2 and J = 2 to J = 3 transitions for CH3NO2 and CD3NO2 have been assigned for several internal rotational states. The best values of the rotational constants B and C were found to be 10 542.7 and 5876.7 Mc/sec for CH3NO2 and 8697.1 and 5254.3 Mc/sec for CD3NO2. The rotational constant for the NO2 group about the symmetry axis is 13 277.5 Mc/sec. These constants are determined assuming no inertial defect, slightly different values are calculated if other assumptions are made. Some of the assigned lines are a very sensitive function of the low barrier to internal rotation. The barrier term V6 was determined to be 6.03±0.03 calories/mole for CH3NO2 and 5.19±0.03 calories/mole for CD3NO2. The term V12 is less than 0.05 calorie/mole. The dipole moment of CH3NO2 is 3.46±0.02 Debye units.
Some Vibration-Rotation Bands of Diazomethane
Authors: Fletcher William H. , Garrett Thomas P.
Published: January 2005

Three parallel fundamentals and one perpendicular overtone have been resolved with a grating spectrometer and the results analyzed. The ground state rotational constants are B″=0.371 cm—1 and A″—B″=8.64 cm—1, and the band origins are ν̃2=2102.2, ν̃3=1414.4, ν̃4=852.3, and ν̃3+ν̃5=4579.3 cm−1. The two skeletal bending bands have been observed with CsBr and KBr prisms and interpreted in terms of strong Coriolis coupling. The fundamental frequencies are approximately 408 and 422 cm—1.
Near Infrared Spectrum of DCl
Authors: Van Horne B. H. , Hause C. D.
Published: January 2005

The first (2—0) and second (3—0) overtones of DCl have been obtained with high dispersion in the 2.4 and 1.6 micron regions. Values for the rotational constants Be, Ie, and re are essentially in agreement with those obtained by Pickworth and Thompson for the fundamental band. The molecular constants obtained are:   DCl35  DCl37Be5.4490 cm−15.432 cm−1Ie5.1354×10−40 g−cm25.1516×10−40 g−cm2re1.2744×10−8 cm1.2745×10−8 cmωe2144.77 cm−12141.20 cm−1ωexe26.92 cm−126.99 cm−1ωeye0.036 cm−10.063 cm−1These agree closely with the values calculated from the data for HCl.
Relaxation of Vibrational Nonequilibrium Distributions. I. Collisional Relaxation of a System of Harmonic Oscillators
Authors: Rubin Robert J. , Shuler Kurt E.
Published: January 2005

A theoretical study has been made of the collisional relaxation of a system of harmonic oscillators prepared initially in a vibrational nonequilibrium distribution. Using harmonic oscillator collisional transition probabilities we have obtained expressions which describe the relaxation of initial nonequilibrium δ-function distributions and Boltzmann distributions to their final equilibrium state. Our results show that an initial Boltzmann distribution with ``temperature'' T0 approaches the final equilibrium Boltzmann distribution at temperature T via a sequence of intermediate Boltzmann distributions with time-dependent ``temperatures'' T0⩾T(t)⩾T for the case T0>T. The initial δ-function distribution relaxes to the final equilibrium Boltzmann distribution via a sequence of nonequilibrium distributions. The study of the relaxation of the mean energy shows that this relaxation depends only upon the mean energy of the initial distribution, and is independent of the form of the initial distribution. The relaxation time for the mean energy was found to be 1/k10θ where k10 is the collisional transition probability per second for transitions between levels one and zero $$Word$$ where θ=hv/kT. The results obtained in this paper pertain to a system at sufficiently high pressure so that radiative transitions can be neglected as compared with collisional ones.
Wavelength Formulas and Configuration Interaction in Brooker Dyes and Chain Molecules
Authors: Platt John R.
Published: January 2005

The zero-order wavelength of absorption, λI, of a conjugated chain of N bonds with all bonds equal is λI=Nλc+λL+λR,where λc is a universal constant, about 500 A per bond, and λL, λR are end-group corrections. The corresponding energy, EI, is modified in second order by configurational mixing of the ground state with a certain excited state, to give within experimental error the observed transition energy E=[EI2+(bL−bR)2]12.The derivation is a simplified adaptation of the ideas of Brooker, Herzfeld, and Sklar. The end-group basicities, bL and bR, or stabilizations of alternative resonance structures, locate the electron density maxima in the chain and determine the bond density alternations and bond length alternations that probably produce the mixing. They are additive and consistent for over 50 end groups and can be derived theoretically in many cases. Their dependence on chain length and solvent is shown. Substituent groups have two parameters, λ, b, as in aromatic ultraviolet spectra.

The changes in transition band widths, vibrational structure, and intensity in changing solvents are accounted for. The strong convergence of polyene series spectra and the nonharmonic spacing of their higher states is attributed to their large b-values, about 20 kK. The corresponding mixing of states is related to the probable character of the excited state wave functions and to the probable strong alternation of polyene bond lengths even in long chains.
Millimeter Wave Spectrum, Molecular Structure, and Dipole Moment of Hydrogen Selenide
Authors: Jache Albert W. , Moser Paul W. , Gordy Walter
Published: January 2005

Several rotational transitions of various Se isotopic species of H2Se and D2Se have been measured in the shorter millimeter wave region. These yield the value of 1.460±0.013 A for the bond length and 91.0°±0.6° for the bond angle. From Stark effect measurements on two of the transitions the value 0.24±0.02 Debye is obtained for the molecular dipole moment.
Rate of Association of n-Propyl Radicals
Authors: Whiteway S. G. , Masson C. R.
Published: January 2005

The rate of association of n-propyl radicals has been measured by studying the photolysis of di-n-propyl ketone in intermittent light. A value of k2′=1×10—8 cc molecule—1 sec—1 at 100° has been obtained. Possible sources of error have been discussed and it is concluded that the above value may be too high by a factor of the order of 20, thus indicating that reaction probably occurs at every collision. A value of k3/k2=0.125±0.01 has been found, where k3 and k2 are the rate constants for disproportionation and combination, respectively.
Rate of Electron Exchange between Cuprous and Cupric Ions in Hydrochloric Acid Solutions by Nuclear Magnetic Resonance
Authors: McConnell H. M. , Weaver H. E.
Published: January 2005

A determination of the Cu63 nuclear resonance line width in concentrated hydrochloric acid solutions containing both cuprous and cupric chloride leads to an evaluation of the bimolecular rate constant k for the electron exchange process Cu+++Cu+→+Cu++Cu++.The experimentally determined value for k is k = 0.5×108 liter/mole-second.
Steady-State Burning of a Liquid Droplet. II. Bipropellant Flame
Authors: Lorell Jack , Wise Henry , Carr Russel E.
Published: January 2005

The flame equations for the steady-state combustion of a liquid droplet are adapted to the case of a bipropellant system. The material transfer of two reactants, fuel and oxidizer, which interdiffuse from opposite directions is considered. As a result, a diffusion flame is established at some distance from the liquid surface. The theoretical analysis is applied to the combustion of an ethanol droplet in oxygen and air, and the effects of various chemical and physical parameters on the burning process are examined.
Infrared Spectrum of Mercuric Chloride and Bromide
Authors: Klemperer William , Lindeman Louis
Published: January 2005

The frequency of the antisymmetric stretching motion in gaseous HgCl2 and HgBr2 has been measured. The bond—bond interaction force constant in these molecules is small.
Refined Theory of Ion Pairing. I. Equilibrium Aspects
Authors: Reiss Howard
Published: January 2005

This paper contains a detailed theory of ion pairing based on the viewpoint that the distribution of pairs is more fundamental than the density of ions in an ionic atmosphere. This distribution is then evaluated by considering the kinetic mechanism by means of which pairs exchange partners. The functions so derived, besides being applicable to nonequilibrium situations, are free of many of the inconsistencies which attend the simple theory of pairing based on mass action considerations. The present paper restricts attention to the properties at equilibrium.
On the Ignition of a Moving Combustible Gas Stream
Authors: Chambré Paul L.
Published: January 2005

The ignition phenomenon in a chemically reactive gas flowing about a heated body is discussed. Specifically the conditions at the forward stagnation point of the object are analyzed. A condition is formulated which relates the critical surface temperature for ignition with those parameters which control the heat and mass transport and the reaction kinetic mechanism.
Theory of the Dielectric Constant at High Field Strengths
Authors: Buckingham A. D.
Published: January 2005

A discussion of the phenomenon of dielectric saturation is presented, and Debye's theory for an assembly of independent molecules is extended to include the field dependence of the molecular polarizability. Also, a rigorous theory of the field-dependent dielectric constant of a dense medium is deduced. It is found that a relationship valid at all densities exists between this dielectric constant and the molecular Kerr constant, and the experimental data on liquid carbon disulfide are in good agreement with the theory. The saturation effect in dilute solutions of anisotropically polarizable substances with large dipole moments is also discussed, and the experimental results for dissolved nitrobenzene agree well with the theory.
Calculation of Vibrational Relaxation Times of the Chloromethanes
Authors: Tanczos Frank I.
Published: January 2005

The Schwartz, Slawsky, and Herzfeld method for the calculation of vibrational relaxation times of gases has been extended in its application to polyatomic molecules. A general method is developed for the calculation of the effective relaxation times and the associated constants of the sound velocity relaxation equation. Calculations have been made for the bimolecular collisions of methane and the chloromethanes involving changes of one, two, and three quanta. A normal coordinate treatment is used to obtain the atomic vibrational amplitudes. The effect of an intermolecular potential function, embodying a dipole interaction term, is included for the polar molecules of this investigation.

Calculated results are compared with experimental data. For CH4 and CH3Cl the calculations agree well with experimental results. For CH2Cl2, CHCl3, and CCl4 the calculated relaxation times are higher than selected experimental values by factors of 8–9. For CH2Cl2, CHCl3, and CCl4 two major relaxation times are calculated. In the case of CH2Cl2 the two relaxation areas have been observed. The experimental data on CHCl3 and CCl4 remain inconclusive in respect to the two predicted relaxation areas. Collisions involving three quanta are shown to be important for CH2Cl2, CHCl3, and CCl4.
Optical Rotatory Dispersion of Helical Polymers
Authors: Moffitt William
Published: January 2005

It is shown that for every transition in its individual residues, a helix has two transitions whose moments are respectively parallel and perpendicular to the screw axis. The largest contributions to the rotational strengths of these bands are equal and opposite in the two cases. As a result, their net effect on the optical activity contains a term proportional to the interval between the two upper states. This term shows abnormal dispersion and its magnitude and sign are more easily interpreted than any other component of the rotatory power.
Vibrational Assignment in Monomeric Formic Acid
Authors: Wilmshurst J. K.
Published: January 2005

The infrared spectrum of formic acid vapor at 150°C has been studied over the 1800–1250 cm—1 region. A vibrational assignment has been made for monomeric formic acid and the anomalous frequency shifts in the three deuterated isotopic acids explained on this assignment by considering vibrational interaction.
First Singlet-Singlet Electronic Transition in the Phenanthrene Molecule and the Band Structure of the Phenanthrene Crystal
Authors: McClure Donald S.
Published: January 2005

The absorption and emission spectra of single crystals of phenanthrene have been studied at 20°K. The data show that the transition moment in the molecule is short-axis polarized, and that the factor group splitting in the crystal is 47 cm—1. The emission originates in a region of very weak absorption at a frequency below the main absorption in analogy to several other molecular crystals whose spectra have been studied. It is suggested that the emitting level corresponds to a distorted lattice site.
Growth Rates of Turbulent Free Flames
Authors: Mickelsen William R. , Ernstein Norman E.
Published: January 2005

Effective flame speeds of turbulent free flames were measured by photographic, ionization gap, and photo-multiplier tube methods; they were found to have a statistical distribution attributed to the random nature of the turbulent field. The effective turbulent flame speeds for the free flame were found to be less than those previously measured for flames seated on Bunsen burners and bluff bodies. The statistical spread of the effective turbulent flame speeds was markedly wider in the lean and rich fuel-air regions. This is attributed to the greater sensitivity of laminar flame speed to flame temperature in the lean and rich regions.
Vibrational Intensities in Halogenated Methanes. II. Methylene Bromide and Methylene Iodide
Authors: Singh Nand Lal , Straley Joseph W.
Published: January 2005

The absolute intensities of the fundamental bands in CH2Br2 and CH2I2 of species B1 and B2 have been measured. The intensities observed are, in cycles/sec at NTP, CH2Br2        CH2I2A614.6×101037.2×1010A748.2×101077.9×1010A81003 ×1010473 ×1010A9616 ×10101109 ×1010The bond moments and bond derivatives calculated from this data are CH2Br2        CH2I2μCH+0.55×10−18+0.5 ×10−18 (B1 vibrations)+0.86×10−18 (B2 vibrations)μCI−0.70×10−18 0 (assumed)∂μCH/∂rCH+0.17×10−10 or −0.10×10−10+0.2 ×10−10 or −0.2×10−10∂μCX/∂rCX+3.27×10−10+2.1 ×10−10where the ambiguity in signs that led to alternate values of ∂μCH/∂rCH could not be resolved.
Thermodynamic Properties of the Titanium Chlorides
Authors: Altman David , Farber Milton , Mason David M.
Published: January 2005

From a series of ten different experiments performed at this laboratory and from experiments reported elsewhere, the following thermodynamic properties have been obtained (ΔHf298 in kcal/mole and S°298 in cal/°C/mole): TiCl4(l), ΔHf298=—191.2; TiCl4(g), ΔHf298=—181.6; TiCl3(s), ΔHf298=—170.7, S°298 =34.4; TiCl3(g), ΔHf298=—128.7, S°298=74.9; TiCl2(s), ΔHf298=—120.6, S°298=24.7; TiCl2(g), ΔHf298 =—69.4, S°298=65.9. A theoretical value for S°298 of 56.1 was calculated for TiCl(g). Estimated values for the Cp of these compounds are also included.
Photolysis of Dimethyl Peroxide
Authors: Takezaki Yoshimasa , Miyazaki Teruhisa , Nakahara Noriko
Published: January 2005

Dimethyl peroxide has been photolyzed in vapor phase by 2537 A-light under various peroxide pressures at temperatures from 21 to 60°C, and for various light intensities at 30°C. The over-all rate was measured manometrically.

The reaction is self-inhibiting and is also greatly inhibited by a small amount of formaldehyde. The initial rate is expressed by AI+BI½[CH3OOCH3]½ (A≪B and I is absorbed light intensity), and it tends to 3I when formaldehyde is added sufficiently. Carbon monoxide, methanol, and formaldehyde were found in the reaction product. The amount of hydrogen was quite small in the normal run and also in the run where much formaldehyde was added. Based on these results the following mechanism has been proposed: CH3OOCH3+hν→2(H+HCHO),H+CH3OOCH3→CH3OH+CH3O,{CH3O+CH3OOCH3→CH3OH+CH3OOCH2,CH3OOCH2→CH3O+HCHO,CH3OOCH2+CH3O→CH3OH+2HCHO.

From the temperature coefficient of the rate, Ea+Eb—Ec= 5.8 kcal, the difference of activation heats, has been obtained; the numerical value is supposed to be the upper limit of Eb.
Infrared Spectra of High Polymers. II. Polyethylene
Authors: Krimm S. , Liang C. Y. , Sutherland G. B. B. M.
Published: January 2005

The infrared spectrum of polyethylene has been obtained between about 3000 cm—1 and 70 cm—1, polarization measurements on oriented specimens having been obtained to about 350 cm—1. Assignments of the fundamentals are made with the help of a group theory analysis. The assignment of the controversial CH2 wagging mode is discussed in detail and especially in terms of new evidence from the spectra of n-paraffins, both as single crystals and as polycrystalline aggregates. It is shown that this mode is to be assigned to a weak band at 1369 cm—1. A satisfactory determination of the bands which arise from CH3 groups is also made possible by a study of the paraffin spectra. The splitting of bands in the spectrum is conclusively shown to arise from interactions between molecules in the crystalline phase. The nature of this interaction is discussed in terms of recent theories.
Infrared Spectra of High Polymers. III. Polytetrafluoroethylene and Polychlorotrifluoroethylene
Authors: Liang C. Y. , Krimm S.
Published: January 2005

The infrared spectra of polytetrafluoroethylene and polychlorotrifluoroethylene have been obtained between 4000 cm—1 and 70 cm—1. Polarization measurements on oriented samples were obtained in the region of 4000 cm—1 to 300 cm—1. It is known from x-ray diffraction studies that both polymers have helical chain configurations. From a factor group analysis of the one-dimensional space group, selection rules and approximate vibrational patterns of the infrared active fundamentals have been derived. A calculation of the normal frequencies of an assumed planar zig-zag chain model of (CF2)n has been made, resulting in a satisfactory assignment of the bands in the infrared spectra of both polymers.
Clapeyron Equation for Multicomponent Systems
Authors: Li James C. M.
Published: January 2005

The Clapeyron equation is derived for a multicomponent system and illustrated with specific examples including the change of dew point with pressure for gaseous mixtures of fixed composition.
Soft X-Ray Absorption Edges of Metal Ions in Complexes. I. Theoretical Considerations
Authors: Cotton F. Albert , Ballhausen Carl J.
Published: January 2005

The effect of crystal field symmetry on the appearance of K x-ray absorption edges of metal ions in complexes is considered. In particular, the splitting of the 1s—4p absorption for first row transition elements is related to the splitting of the degeneracy of the 4p energy levels in the ion by the crystal field.
Scattering of High Velocity Neutral Particles. VII. Xenon—Xenon
Authors: Amdur I. , Mason E. A.
Published: January 2005

Measurements have been made of the scattering of xenon atoms with energies between 700 and 2100 ev in room temperature xenon. The interaction potential for two xenon atoms, deduced from the variation of total collision cross sections with energy, may be expressed as V(r)=1.13×10−8/r7.97 ergsfor r between 3.01 A and 3.60 A. This potential is consistent with others, valid at larger separation distances, which have been obtained from measurements of gaseous compressibility, transport, and crystal properties, within the limits of uncertainty of the potentials at the larger distances.
Scattering of High Velocity Neutral Particles. VIII. H–He
Authors: Amdur I. , Mason E. A.
Published: January 2005

Total collision cross sections have been measured for hydrogen atoms with energies between 700 and 2100 ev, scattered in room temperature helium. The results have been analyzed to obtain potential energy information for the interaction between a hydrogen atom and a helium atom. The potential function, which may be represented by V(r)=3.75×10−12/r3.29 ergfor r between 1.16 A and 1.71 A, gives values which agree with those calculated quantum mechanically by Mason, Ross, and Schatz.

The H–He potential has been combined with a potential previously obtained for He–He to obtain a function which, it is suggested, represents the repulsive interaction between two hydrogen atoms. The derived function is in fair agreement with theoretical calculations of Hirschfelder and Linnett for the repulsive 3Σ state of the hydrogen molecule.
Solubility of Lithium in Doped and Undoped Silicon, Evidence for Compound Formation
Authors: Reiss H. , Fuller C. S. , Pietruszkiewicz A. J.
Published: January 2005

The solubility of lithium in silicon from a lithium-silicon alloy phase has been redetermined. The original data of Fuller and Ditzenberger appear to be in error. The solubility of lithium, from the same phase, in boron-doped silicon has also been determined. At both low and high temperatures the solubility in the doped crystal markedly exceeds that in the undoped one. In fact, the solubility just about equals the boron concentration in these ranges. The low temperature disparity can be explained in terms of hole-electron equilibria while the high temperature effect is believed due to covalent bond formation between lithium and boron. A quantitative theory is developed which predicts the experimental results.
Infrared Spectrum of Methyl Isocyanide
Authors: Williams R. L.
Published: January 2005

The infrared spectrum of methyl isocyanide vapor has been remeasured with medium resolving power from 1.7–10μ and in the far infrared region around 38μ. From these observations it has been possible to obtain unequivocally the three degenerate fundamental vibration frequencies v6, v7, and v8, and the symmetric frequency v3. Thermodynamic properties are calculated for the molecule. In addition the spectrum of acetonitrile vapor has been remeasured abound 6μ with slightly increased resolving power and the v3 and v6 fundamental frequencies obtained.
Osmotic Pressure Phenomena as Observed in Silver Membrane Osmometers
Authors: Barr T. A.
Published: January 2005

Two features of aqueous polyethylene glycol solutions (molecular weights 285 to 6600) have been noted in experiments with silver membrane osmometers: first, the solutions can be forced through the membranes in a manner which is indicative of capillary viscous flow; second, the osmotic pressures of polyethylene glycols are such that the limits of the reduced osmotic pressure as the concentration tends towards zero are of the form KMα, when K and α are positive numbers, instead of RT/M as is indicated by thermodynamic theory. The differences between theoretical and observed osmotic pressures are interpreted as being due to diffusion of solute through the membranes. On this basis diffusion coefficients are calculated for the diffusion of polyethylene glycol through the membranes. For an estimated molecular weight of 400 000 the membranes are semipermeable. Similar work has been done on polystyrenes (molecular weights 180 000 to 673 000) and the membrane are shown to be semipermeable for polystyrenes of molecular weights greater than 500 000.
Distribution of Vibrational Frequencies of a Crystal by Fourier Transformation of the Heat Capacity
Authors: Taylor William J.
Published: January 2005

It is shown that when represented on a logarithmic temperature scale a thermodynamic function is the resultant or convolution of the frequency distribution function and a function characteristic of a single oscillator. The inversion to yield the frequency distribution function may be accomplished by means of a theorem on the Fourier transform of a resultant. The method is related to that of Montroll, but may be in a more practical form for calculation. The present formulation also yields a quantitative expression for the error in the frequency distribution function which shows the importance of adequate smoothing of the experimental data.
l-Type Doubling in N2O
Authors: Shearer J. N. , Wiggins T. A. , Guenther A. H. , Rank D. H.
Published: January 2005

Doublet separations in nine π—π bands of the linear nonsymmetrical molecule N2O have been measured in the region 1.5–2.4 μ. In addition to the doublet splitting caused by the ν2 motion, it is shown that the parallel modes ν1 and ν3 contribute measurable amounts to this splitting in π states, so that the doubling constant qν is a function of all three vibrational quantum numbers νi. The data fit an equation of the form qv=Σi Qi(vi+1) within experimental error, where i = 1, 2, 3, and the Qi are called the Coriolis constants. The experimentally determined values are Q1 = 1.40×10—4, Q2 = 3.40×10—4, and Q3 = —0.19×10—4 cm—1.
Rotation-Vibration Spectra and the Molecular Constants of Cyclopropane and Cyclopropane-d6
Authors: Günthard Hs. H. , Lord R. C. , McCubbin T. K.
Published: January 2005

The parallel fundamental infrared bands of cyclopropane at 3101 cm—1 and cyclopropane-d6 at 2336 cm—1 have been studied at high resolution. The ground-state rotational constants B″, whose values are found to be 0.6696±0.0028 and 0.4630±0.0023 cm—1, respectively, yield a value for the C – C distance of 1.524±0.014 A and a functional relationship between the C – H distance and the HCH angle. If the C – H distance is assumed to be 1.07 A, the HCH angle appears to have a value just above 120°. A normal-coordinate treatment yields force constants and eigenvectors for vibrations of species A1′, A2″, E′, and E″. Zeta constants of vibration-rotation interaction for species E′ have been calculated for both cyclopropane and cyclopropane-d6.
Comparison of Force Constants in Radicals and Molecules. The Halides of Zinc, Cadmium, and Mercury
Authors: Klemperer William
Published: January 2005

The infrared spectra of the molecules of HgI2, CdCl2, CdBr2, CdI2, ZnI2, ZnBr2, and ZnCl2 have been observed in the region of the fundamental frequency of the antisymmetric stretching motion. A comparison is made between the bond stretching force constants of these molecules together with HgCl2 and HgBr2 and the force constants of the related diatomic monohalides. As a group the dihalides exhibit different trends in their force constants than the monohalides.
Intensity and Line-Width of the 15-Micron CO2 Band, Determined by a Curve-of-Growth Method
Authors: Kaplan Lewis D. , Eggers David F.
Published: January 2005

The intensity of the 15 μ band of CO2 has been redetermined by a curve-of-growth method, utilizing simple formulas derived for the absorption coefficient of the Q branch. The value obtained is 240 cm—1 per cm at S.T.P., some 25 to 30% higher than the results of the Wilson-Wells method. Extrapolation methods in general can lead to considerable underestimation of intensity, especially when applied to bands containing narrow Q branches.

The nitrogen-broadened half-width at one atmosphere and 298K is 0.064 cm—1.
Transport Properties of a Dense Fluid of Hard Spheres
Authors: Longuet-Higgins H. C. , Pople J. A.
Published: January 2005

From the two assumptions, that the pair distribution function of relative position is independent of the rate of strain or the temperature gradient and that the velocity distribution is locally Maxwellian, expressions are derived for the shear viscosity η, the bulk viscosity κ and the thermal conductivity λ of a hard-sphere fluid at high densities. An expression is also derived for the coefficient of self-diffusion D at any density by assuming that the autocorrelation function for the velocity of a given particle decays exponentially. The results are η=4a5(mkTπ)12(PkT−NV),λ=2ak(kTπm)12(PkT−NV),κ=4a3(mkTπ)12(PkT−NV),D=a2(πkTm)12(PVRT−1)−1,where m and a are the mass and radius of the spheres.
Isotropic Hyperfine Interactions in Aromatic Free Radicals
Authors: Weissman S. I.
Published: January 2005

It is shown, by a procedure similar to one used by Abragam, Horowitz, and Pryce in their studies of hyperfine structure in paramagnetic ions and atoms, that configurational interaction may contribute to the isotropic hyperfine interaction in free radicals. For a configurational admixture of the type (σB)2(π)+λ(σB) (σA) (π), the hyperfine interaction is 32π/3√6μημeλσB(rη)σA(rη) where μe and μη are magnetic moments of the electron and the nucleus η, and σ(rη) is the magnitude of the orbital σ at the position of the nucleus. Since the hyperfine coupling is linear in λ, only small admixtures of excited configurations are required to account for the proton hyperfine splittings observed in aromatic free radicals.
Chemical Effects of Ultrasonics—``Hot Spot'' Chemistry
Authors: Fitzgerald Mary Evelyn , Griffing Virginia , Sullivan James
Published: January 2005

The present work was undertaken with the purpose of considering why and how reaction takes place in an ultrasonic field, rather than studying the chemical kinetics of such reactions. Experimental evidence is presented which supports the conclusions that chemical processes brought about by ultrasonics require cavitation. Furthermore, the experiments were planned so as to show whether the reactions take place in the bubble or at the interface by studying the effect of the thermal conductivity and of the ratio of the heat capacities of various dissolved gases and their mixtures on the yields. From the results it was concluded that primary reactions seem to be gas phase reactions, probably of a thermal nature, taking place inside the gas bubbles which serve as ``hot spots'' in the liquid. The calculations show that, under the experimental conditions reported here, temperatures of several hundreds or thousands degrees can be easily reached inside the cavitating bubbles in resonance with the sound field; it is believed that at these temperatures the reaction which gives rise to H2O2 takes place. At this time it is not possible, however, to rule out completely the concomitant effects of gaseous discharge as suggested by others. It was also found that in conducting experiments like those in the present work, the cavitation threshold should be determined, effective intensities used, and systems maintained as simple as possible.
Substituted Methanes. XXVII. Potential Constants and Calculated Thermodynamic Properties for CH2F2, CHDF2, and CD2F2
Authors: Meister Arnold G. , Dowling Jerome M. , Bielecki Anthony J.
Published: January 2005

Using the Wilson FG matrix method, potential constants were determined for the CH2F2 molecule using the most general quadratic potential function. The same constants were used to calculate the wave numbers of the fundamentals of the CHDF2 and CD2F2 molecules. Finally, the heat content, free energy, entropy, and heat capacity were calculated for all three molecules for 12 temperatures from 100° to 1000°K, for the ideal gaseous state at 1-atmos pressure.
Fluorine Magnetic Resonance Spectra of some Mono- and Disubstituted Tetrafluorocyclobutanes
Authors: Phillips W. D.
Published: January 2005

The fluorine magnetic resonance spectra of a series of tetrafluorocyclobutane molecules substituted unsymmetrically with respect to the plane of the cyclobutane ring are reported. The complex spectra of these compounds are interpreted in terms of nonequivalence of fluorine atoms bonded to a common ring carbon atom. Nonequivalence of fluorine atoms bonded to a common carbon atom is discussed in terms of restricted rotation about C–C bonds in cyclic structures and possible intramolecular interaction mechanisms for producing the nonequivalence.
High-Temperature Thermodynamic Properties of Uranium Dioxide
Authors: Ackermann Raymond J. , Gilles Paul W. , Thorn R. J.
Published: January 2005

Effusion measurements have been carried out with uranium dioxide over a temperature range from 1600° to 2800°K and a pressure range from 10—8 to 6 mm. Four different isotopic compositions, three different effusion cells and two different apparatuses were used. The results are concordant and demonstrate that the oxide vaporizes congruently in this range. The cubic (fluorite) lattice parameter of the congruently vaporizing composition, UO2.00, is 5.4588±0.0002kX.‡ All higher oxides will yield UO2.00 when heated above 1300°C in a vacuum of 10—6 mm Hg. A least-squares analysis of the data yields for the total volatility, calculated as the dioxide, the equation, logp (mm)=13.298−3.7195×104T+3.5162×106T2+2.6178×109T3,and reveals a pronounced positive curvature at the higher temperatures. It is doubtful that this curvature arises from a deviation of the flow rate from that predicted by kinetic theory, and hence it must be caused by two vaporization processes. The volatility of a uranium and uranium dioxide mixture shows that no gaseous suboxides are important. The principal vapor species at the lower temperatures (1600–2000°K) is undoubtedly UO2 for which the vapor pressure is given by logp (mm)=(−33,115±371)/T−4.026 logT+25.686±0.205.The heat and entropy of sublimation are 137.1±1.7 kcal/mole and 36.4±0.9 eu at 1800°K and 159.6 kcal/mole and 49.4 eu at 298°K. The heat of sublimation at absolute zero is estimated to be 160 kcal/mole with an estimated uncertainty of 5 kcal/mole. This value leads to 14.4 ev for the dissociation energy for gaseous UO2. The positive curvature cannot be caused by solid monoxide or gaseous UO3 on the basis of existing thermodynamic data. It is postulated that the curvature is caused by a dimer U2O4(g) which becomes important at the high temperatures. Its vapor pressure is represented by logp (mm)=(−38 221/T)+14.056.The heat and entropy of dissociation of the dimer are 88.9 kcal/mole and 16.6 eu at 2450°K. Crude absolute entropy calculations indicate this entropy change to be reasonable.
Modified Atomic Orbital Method. II. The Electronic Structure of the Oxygen Molecule
Authors: Itoh Takashi , Ohno Kimio
Published: January 2005

A modified form of the nonempirical atomic orbital method, shown previously to be considerably successful in calculating the electronic energy levels of the ethylene molecule, is now applied to the computation of the lower excited π-electron levels of the oxygen molecule. The results of the calculation are again satisfactory in that they are almost as good as those obtained by the semiempirical methods of Moffitt and of Fumi and Parr.