The Rigaku Journal
Vol. 6/ No. 2/1989

Product Information

THE WORLD OF THE INTEGRATED RIETVELD ANALYSISSYSTEM FAT-RIETANA MESSAGE TO USERS OF THE RIGAKU VERSIONFUJIO IZUMINational Institute for Research in Inorganic Materials, 1- 1 Namiki, Tsukuba, lbaraki 305, Japan

A Rietveld analysis program RIETAN is the one
and only software that can be applied to the refinement of intensity data measured by any of angledispersive X-ray diffraction (including SR), angledispersive neutron diffraction and TOF neutron diffraction in virtually the same procedu re. (1 ),(2 ) Thisprogram has lots of features for crystallographic calculation and is so user-friendly that even the novice atcomputer or crystal analysis can easily run it. It is
designed to have the computer make up for user's
want of ability and experience. Thus, in Jappn,
RIETAN has already established its position as a defacto standard of Rietveld analysis programs. Most
educational and research institutions and private
businesses now employ RIETAN.
One of the salient features of RIETAN is theprovision of manuals that contain exceedingly minuteexplanations. For instance, a manual for angledispersive diffraction contains pages as many as 130.
RIETAN may be said to be a rare program for crystallographic computation in Japan because it has suchthoroughgoing documentation. These manuals not
only scrupulously cover information required for awide range of users, both beginners and experts ofcrystal analysis alike, but also contain detailed descriptions not found in conventional manuals. Notable inparticular are explanations in a simple style about thatminimum knowledge of crystallography by citing
examples which is indispensable for running
RIETAN, such as how to read "International Tables",the meanings of symmetry operations, complex lattices, equivalent positions, temperature factors, and soon. Such descriptions are very favorably received(1)

F. Izumi: Nippon Kessho Gakkai Shi (J. Crystallogr. Soc. Jpn.,
in Japanese), 27, 23 (1985).
(2)
F. lzumi, H. Asano, H. Murata and N. Watanabe: J. Appl.
Crystallogr., 20, 411 (1987).
(3)
F. Izumi: RIGAKU J., 6, No. 1, 10 (1989).

37

because they have hitherto been entirely omitted fromconventional software packages associated with crystallography. Besides, a detailed report on the newest
version of this program (3) is also available.
The weakest point of a previous version ofRIETAN was that it was "isolated" software. Because
it was not connected to other programs for crystallographic calculation, users had to reenter basic input
data on symmetry operations, atomic names, etc.
along with results of refinement (structure parameters, lattice constants and their standard deviations) at the time of running the related programs.
Parameters refined by Rietveld analysis are no morethan expressionless numbers. Needless to say, thewhole aspect of crystal structure analysis can beunderstood only after the validity of a structure model
is checked by Fourier (D) synthesis, interatomic
distances and bond angles are calculated, and crystal
models are plotted. However, because reentry of theabove data was a terribly troublesome "dirty work",
RIETAN users including me always tended to neglect
utilization of the related programs, which leads todilution of the significance of Rietveld analysis despite collection of intensity data over long hours.
It was toward the end of 1987 that Rigaku Corporation set on the work of modifying RIETAN to amenu-operation system. I checked menus as theycame out bit by bit from Rigaku and indicatedimprovements to be made. What I noticed soon wasthat unless a variety of related programs should beconnected to RIETAN in such a way as to enable
execution of them without the need of reentries,
RIETAN would lose much of its raison d'&tre ascommercial software. Without the provision of such
related programs from the maker side, it would be
difficult for users to connect these programs toRIETAN by themselves unless they have accumulated expert knowledge about crystal analysis.
The Rigaku Journal

Even if they succeeded in obtaining the related
programs, it would be almost impossible for them totransport it to a computer which is connected to apowder diffractometer in use or to redesign it to amenu-operation system or to connect it to RIETAN.
Such software, if available, must be also useful tothose who run RIETAN on mainframe computers.
With the above idea in mind, I started integrationof the Rietveld analysis system in June or so of the following year. The new system to be born was given adevelopment code, FAT-RIETAN (stout-size RIETAN). Efforts were devoted at the same time to polishup the substance of RIETAN, especially the output
feature of crystallographic data. The progress of programming work was slow, however, partly because I
was busily engaged in research and others at that timein the aftermath of "superconductivity fever". Finally,in February 1989, the connection to ORTEP-II, thelast phase of the work, was completed, and thereby
RIETAN was reborn from a naive stand-alone software to a full-fledged integrated system.
In the Rigaku version of the FAT-RIETAN
system, the following programs (¬ - ±) and data bases(² - ´) are organically combined with each other toproduce a harmonious, integrated environment. Theenvironment thus prepared not only allows Rietveld
analysis and simulation of powder diffraction patterns
but also makes other crystallographic calculations
easily challengeable.
¬ RIETAN
The Rietveld analysis of X-ray powder diffraction
data. It is also possible to simulate X-ray powder
diffraction patterns of compounds whose structures have already been analyzed.
- GENREF
Calculation of the diffraction indices and peak
positions of a compound whose space group isknown. It can also compare the obtained peak positions with an observed pattern so as to examine thediffraction indices and presence of impurities.
® FRS
Fourier and D syntheses based on Fo estimated fromthe results of Rietveld analysis so as to plot contourmaps.
¯ ORFFE
Calculation of interatomic distances and bondangles. This program is characterized by procedures for calculation of precise standard deviations.

Vol. 6 No. 2 1989

° ORTEP-II
Drawing of crystal structure models. This program has surprisingly abundant functions and is
excellent in representing anisotropic thermal vibrations. In FAT-RIETAN, macro instructions forcrystal model plotting are translated into instructions for ORTEP-II with a preprocessor calledPRETEP.
± LATTEN
Calculation of Madelung potentials by Ewald's
method.
² SPGRI
A data base containing information on 230 spacegroups described in "International Tables", Vol. 1.
³ SPGRAA data base containing information on 230 spacegroups described in "International Tables", Vol. A.
´ ASFDCA data base containing coefficients for calcula-tionof atomic scattering factors as well as correction
terms for anomalous dispersion and atomicweights.
Provided in addition is a file manager to efficiently
carry out copying, deletion, conversion, etc. of various files. All of these programs are capable of menu
operation so that users can devote themselves toanalysis without being aware of the presence of theoperating system which is running behind FATRIETAN.
A drawback of menu operation is troublesome
menu selection with a mouse. This is felt more andmore as an operator gets familiar with the way ofrunning programs. Another such drawback is that
there are frequent occasions where users cannot makefull use of program features. This tendency is stronger
in particular with RIETAN, ORTEP-II or otherprograms which have many features and need a large
amount of input data. The FAT-RIETAN system(Rigaku version) is designed to allow a jump to any
optional entry section at the time of reediting input
data, but even so it does not mean a solution to thelatter problem. To cope with this, consideration isgiven in RIETAN and ORTEP-II so that the user canalso directly edit input files with a full screen editor(vi or an optional Hitachi Editor).
What should be emphasized here is the educational significance of the FAT-RIETAN system.
RIETAN and its related programs include most of
crystallographic calculations required for single

38

crystal X-ray analysis except for an importantanalytical process for solving the phase problem(4).
Accordingly, this software group must be not only
useful for development and identification of materials
but also effective for the novice to learn the fundamentals of crystallography. Since for a long period, it
has been my earnest wish that not only a handful ofpeople who possess expensive four-circle singlecrystal X-ray diffractometers but those who areroutinely using powder diffractometers be familiarized with crystallography through RIETAN which isoffered to help their studies. RIETAN is a massive
program containing nearly 9000 lines. It lavishly usesarrays, moreover, in order to enhance the computation
speed. As a result, it can hardly be run on conventional
16-bit personal computers. Intensity data had to betransferred to a large computer for analysis. No matter
how excellent anysoftware may be, it is difficuitto
expect its wide spread if it needs access to a large
computer where file handling is troublesome, functions of editors are very poor, JCL is necessary, and an
exorbitant charge for using has to be paid. I was
therefore under the impression that for some timeahead it would be impracticable to run RIETAN on acomputer connected to powder diffractometers.
When the development of a new diffractometersystem, D/max-1000, was started, Rigaku madestudies on the selection of a suitable computer but
failed to reach an internal consensus. The matter wasleft as a pending issue. I happened to visit Rigaku inJune 1987 and was asked for an advice on a computer
for the D/max-1000 system. I recommended without
hesitation the use of a 32-bit workstation with UNIX
as an operating system. Since UNIX is a "seasoned"OS, it can be operated reliably without being troubled
by bugs. Moreover, its multitask and multiwindow
capabilities are fitted for simultaneous execution of(4)For the solution of the phase problem, what most users of fourcircle diffractometers carry out is merely the utilization of thedirect method as a "black box". No particular high-level
crystallographic knowledge is used for this purpose.

39

measurement and data processing on separate windows. I must admit here that in recommending so,
there was somewhat an underlying motive in me totransport RIETAN to the Rigaku system. Surprisingly
enough, anyway, Rigaku instantly decided on thesame day to employ a 32-bit UNIX machine for
D/max-1000. Thus, my long cherished wish to carryout Rietveld analysis while simultaneously measuring
diffraction data with a multitask and multiwindow
system was at last fulfilled, although I made due efforts myself, too, to attain it. The significance of onthe-spot run of various crystallographic calculations(drawing) realized by the completion of the FATRIETAN system must be said immeasurable.
The RIGAKU version of the FAT-RIETAN
system is the very product that has come out upon
joint development by me and Rigaku Corporation. Its
performance and ease of use have been thoroughly
checked by us. As such, it is the only commercial
software at present that can be safely recommended
by me who created the original version. It has now left
its developer's hand and is being routinely operated byusers. During the process of such use, many morepoints to be improved will surface. I am eager to growthis software further to a more friendly and morerefined one by positively incorporating users' requirements and new analytical procedures. It is my wish tomature it to a point where it can render full service as abridge between powder diffractionists and crystallography. To this end, I welcome comments and information from users who may find problems or bugs
upon actual run. I intend to cope with such matters as
best as possible.
Lastly, I would like to express my sincere thanks
to Mr. Masahiko Saito, Engineering Department ofRigaku Corporation. He took charge of actual
modifications toward menu operation. He met my minutest requests and wrote programs, in the C
language, containing lines as many as 7000 in total.

The Rigaku Journal