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Computer Programs
for
Peak Analysis
and
Quantification

This information is taken from Smith and Gorter (1991). For addresses of authors, readers are directed to this reference.


Table A1: CODES USED IN THE PROGRAM LISTS
PROGRAM LANGUAGE
A ASSEMBLY GWB GW Basic
Alg ALGOL P PASCAL
B BASIC QB QUICK BASIC
C C TB TURBO BASIC
F FORTRAN IV, 77, ANSI TC TURBO C
GFA ATARI TP TURBO PASCAL


COMPUTER TYPE
MF Main Frames: CDC, Cray, IBM, PDP, VAX
PC Personal Computer: IBM, MAC
TS Time-Sharing
O Other Types ENCORE, FACOM, PRIME


DISTRIBUTION FORM OF PROGRAM CODES
S Source Code
E Execution Codes Only
EK Key Required to Run
EP Execution Codes Only with Permission
of Philips Netherlands


COSTS AND CONDITIONS FOR DISTRIBUTION OF CODES
Commercial Product
Free
Lease and Fee
Small Fee <$100
$$ Large Fee >$100
FL Free for noncommercial users, Lease
and Fee for commercial users


TYPE OF DOCUMENTATION
DF Machine-Readable Documentation
M Manual
N No documentation
R Reference


PROGRAMS SUPPORT
A Author support
N No support
blank No indication


PROGRAM SOURCES
PEB Program is available from the Powder Diffraction
Software Exchange Bank of the Dutch Association
of Crystallographers.
* Source address or reference not available
OLD An old program available from many sources


Table A2 PROFILE FITTING - DECOMPOSITION
Computer
Program Lang. MF PC Form Cost Supp. Doc. Source
ABFfit F,P + + E $$ A M Antoniadis
et al.
AUTOPEAK F + - S F A DF RAL
CUVFIT + - Wang et al.
DIFFRACT-T/FIT F,A - + E C A M SOCABIM
DOREES F,P + - E $$ A DF Jansen
FIT TC - + E F A R Petkov- Bakaltchev/PEB
KET, KETA F - + E $$ A M Vladimiz
LAT1 F + - S F A R Tran
LSQPROF F,P + - E $$ A DF Jansen
MicroSHADOW F - + EK C A M QJohnson
PEAK F + + E $$ A M GUFI
Pi'oPiliPa'a F + - S F A M Jones
POWDER Rossel/Scott
POWDERPATTERN F + - S F R Hubbard/Pyrros
PROFAN F + - S $ A R Will et al.
PROFAN/PC TP - + S F A R Merz et al.
PROFIT F + + S $$ A M Sonneveld/ Langford
PRO-FIT F + - S F A R Toraya/PEB
REGION F + - S Hubbard/Pyrros
SCRAP F + - Cooper
SHADOW F + - S F A DF SHoward/PEB
TOFMANY F + - S F A DF IPNS
TXTPVGT TP - + S $ A DF Bourniquel et al.
XRAYL F + - S F A Zhang/ Hubbard


Table A3 PROFILE FITTING - FULL PATTERN
Computer
Program Lang. MF PC Form Cost Supp. Doc. Source
ALLHKL F + - S F A DF Pawley
EDINP F + - E $ A R Pawley
FINAX F + - S $ A R Hovestreydt
FULLPROF F + + E F A DF Rodriguez-Carvajal
POWLS F + + S $$ A M Will
PROFIT F - + S F N M Scott
WPPF F + - S F A DF Toraya


With the availability of accurate digitized diffraction traces, peak analysis is becoming a very popular option for locating peaks and for determining the profile parameters. The terminology of profile analysis is confusing for diffractionists who are starting this type of analysis. The programs in this section are correctly classified as decomposition programs. Each of these programs uses a predetermined profile either defined analytically or "learned" from an isolated peak to fit all the other peaks in the pattern including the a2 component. This procedure is to be distinguished from deconvolution which is a Fourier analysis of the peak shape. There are several ways to approach the problem of decomposition.

First, the peaks can all be considered as independent, and each profile can be fit using free parameters. Usually, the profile shape is fixed and the parameters of peak intensity, profile half-width, and peak position are varied. The relative positions of the α1 and the α2 components are known, and their intensity ratios are fixed at 0.5. Where there is a mixture of phases, the peak shape may vary among the phases. If crystallite size is a factor and the crystallite shape is non-spherical, the half-width may vary within the peaks of the same phase. It should be apparent from this discussion that no single program can be optimized for all these options.

The programs listed under the heading "Profile Fitting - Decomposition" differ from the ones listed under "Profile Fitting - Full Pattern" in the way the peaks are treated. In the former category, each peak is generally considered as independent of the other peaks even in a cluster, and usually only a limited range of the pattern is considered during each application of the program. In the latter category, all the peaks (or a large number) in the pattern are considered at one time. If the sample is single phase, all the peak positions are related, and the program should constrain the peak locations to those compatible with a unit cell. Usually, the profile shape is also constrained. The purpose of this approach is to resolve individual peaks, so that the intensities can be determined. The single goal of this approach is to obtain intensities for crystal structure analysis. These intensities can then be used with the usual single-crystal analysis programs which employ direct methods and Patterson analysis. All the programs in this section operate on the full pattern to provide individual intensities.


Table A4 QUANITATIVE ANALYSIS
Computer
Program Lang. MF PC Form Cost Supp. Doc. Source
ARCOQUANT F + - S $$ A DF DSmith
DBW-4.1 F + - S F A M Bish/SHoward
DBW3.2S F + - S F A M Young
DBW3.2 (Mod. PEB) F + - S F A M Wiles-Young/PEB
FAZAN F,P - + S $$ A DF Burova et al.
GMQUANT F + - S F A DF DSmith/PEB
HOWARD-2.0 F + - S F A M SHoward
LSQX F + + C A N Vonk
MicroQUANT F - + EK C A M QJohnson
++PADS++ F - + E C A WASSERMANN
PC/PEAKS C - + S C A M Hill/Foxworthy
PC/QXRD F - + S $$ A M Hill
PFLS F + - S F A R Toraya
PLUVA F + - $$ A DF Schenk
QPDA F + - E F A M Hill/Madsen
QUANT85 F + - S F A M Hubbard/Snyder
RIMPAC GWB - + E $$ A M Davis
SIROQUANT F - + E C A M Taylor


Quantitative phase analysis by X-ray powder diffraction is one of the few techniques which is truly phase sensitive rather than element sensitive. The first applications followed the development of the theory by Alexander and Klug (1948). Although the technique was applied effectively to some special problems, the data collection was laborious and limited the general application of the method. When the APD became the data collector, the data was easier to analyze, and the technique saw enhanced use in the 1980's which has continued to the present time.

There are basically three ways of doing quantitative analysis at the present time. One technique uses integrated intensities (areas) of individual peaks for each of the phases in the mixture if peaks are resolvable and clusters of peaks when they are not. With the raw data in digitized form, it is easy to integrate the desired diffraction ranges for the calculation. QUANT85, PC/PEAKS, MicroQUANT and RIMPAC use this approach. GMQUANT and ARCOQUANT use the full diffraction trace with a reference database of digitized traces of reference patterns. The other programs are Rietveld programs modified to emphasize the quantification of phases in a mixture by adjusting the pattern scale factors for absorption effects. All these approaches are effective if the sample preparation problems can be overcome.