========================================================================== ========================================================================== DDDDDDD IIII CCCCCC VV VV OOOOOO LL 0000 66 DD DD II CC CC VV VV OO OO LL 00 00 66 DD DD II CC VV VV OO OO LL 00 00 66 DD DD II CC VV VV OO OO LL 00 00 66 66 DD DD II CC VV VV OO OO LL 00 00 66 66 DD DD II CC CC VVVV OO OO LL LL 00 00 66 66 DDDDDDD IIII CCCCCC VV OOOOOO LLLLLLLL 0000 66666 ========================================================================== ========================================================================== TWO OPTIONS ARE AVAILABLE WITH DICVOL06 --------------------------------------- >> OPTION 0 IS DICVOL04 (OPTIMISED SEARCH TO BE USED WITH NORMAL QUALITY DATA) >> OPTION 1 OFFERS AN EXTENDED (EXHAUSTIVE) SEARCH (FOR DIFFICULT CASES) [COMPARED TO DICVOL04 (2004) ONLY ONE ADDITIONAL INPUT PARAMETER IS ADDED IN DICVOL06, i.e. OPTION IN CARD 5 (SEE BELOW)] -------------------------------------------------------------- -------------------------------------------------------------- -------------------------------------------------------------- | TO EXECUTE THE PROGRAM, ENTER : DICVOL06 | | | | THEN, ENTER THE INPUT FILE NAME and OUTPUT FILE NAME | -------------------------------------------------------------- -------------------------------------------------------------- -------------------------------------------------------------- PROGRAM FOR THE AUTOMATIC INDEXING OF POWDER DIFFRACTION PATTERNS BY THE SUCCESSIVE DICHOTOMY METHOD. ------------------------------------------------------------------ >>>> THE REFERENCE FOR THIS PROGRAM, TO REPORT IN PUBLICATIONS, IS: >>>> (1): A. Boultif & D. Louer, J. Appl. Cryst. 37, 724-731, 2004 ------------------------------------------------------------------ THE FOLLOWING CRYSTAL SYSTEMS CAN BE ANALYZED: CUBIC, TETRAGONAL, HEXAGONAL, ORTHORHOMBIC, MONOCLINIC AND TRICLINIC. PRECURSOR PROGRAMS: P1 & P2 (REF. 2), DICVOL (REF. 3), DICVOL91 (REF. 4), DICVOL04 (REF. 1) ======================= FOR FURTHER INFORMATION CONTACT D. LOUER E-MAIL Daniel.Louer@free.fr OR A. BOULTIF LABORATOIRE DE CRISTALLOGRAPHIE DEPARTEMENT DE PHYSIQUE FACULTE DES SCIENCES EXACTES UNIVERSITE MENTOURI - CONSTANTINE 25000 CONSTANTINE - ALGERIE TEL./FAX (213) 31 61 47 47 E-MAIL ABoultif@ifrance.com --------------------------------------------------------------- | G E N E R A L I N S T R U C T I O N S | --------------------------------------------------------------- DICVOL PROPOSES SOLUTIONS; THE USER DISPOSES OF THEM. THE AUTHORS DISCLAIM RESPONSABILITY FOR ALL USE OF THIS PROGRAM --------------------------------------------------------------- ===> BEFORE USING DICVOL06, PLEASE READ REFERENCE 1, AS WELL AS THE ===> INSTRUCTIONS AND RECOMMENDATIONS BELOW. _______________ INPUT DATA FILE --------------- CARD 1 TITLE FREE FORMAT CARD 2 N,ITYPE,JC,JT,JH,JO,JM,JTR FREE FORMAT N NUMBER OF LINES USED FOR SEARCHING SOLUTIONS. (This number is, generally, lower than the number N_TOTAL of input lines). e.g. N = 20. ITYPE SPACING DATA TYPE. =1 THETA BRAGG ANGLE IN DEGREES. =2 2-THETA ANGLE IN DEGREES. =3 D-SPACING IN ANGSTROM UNIT. =4 Q SPECIFIED IN Q-UNITS AS E+04/D**2. JC =0 CUBIC SYSTEM IS NOT TESTED. =1 CUBIC SYSTEM IS TESTED. JT =0 TETRAGONAL SYSTEM IS NOT TESTED. =1 TETRAGONAL SYSTEM IS TESTED. JH =0 HEXAGONAL SYSTEM IS NOT TESTED. =1 HEXAGONAL SYSTEM IS TESTED. JO =0 ORTHORHOMBIC SYSTEM IS NOT TESTED. =1 ORTHORHOMBIC SYSTEM IS TESTED. JM =0 MONOCLINIC SYSTEM IS NOT TESTED. =1 MONOCLINIC SYSTEM IS TESTED. JTR =0 TRICLINIC SYSTEM IS NOT TESTED. =1 TRICLINIC SYSTEM IS TESTED. CARD 3 AMAX,BMAX,CMAX,VOLMIN,VOLMAX,BEMIN,BEMAX FREE FORMAT AMAX MAXIMUM VALUE OF UNIT CELL DIMENSION A, IN ANGSTROMS. (IF AMAX= 0.0 DEFAULT= 25. ANGSTROMS) BMAX MAXIMUM VALUE OF UNIT CELL DIMENSION B, IN ANGSTROMS. (IF BMAX= 0.0 DEFAULT= 25. ANGSTROMS) CMAX MAXIMUM VALUE OF UNIT CELL DIMENSION C, IN ANGSTROMS. (IF CMAX= 0.0 DEFAULT= 25. ANGSTROMS) VOLMIN MINIMUM VOLUME FOR UNIT CELLS IN ANGSTROMS**3. VOLMAX MAXIMUM VOLUME FOR UNIT CELLS IN ANGSTROMS**3. (IF VOLMAX= 0.0 DEFAULT= 2500. ANGSTROMS**3) BEMIN MINIMUM BETA ANGLE FOR MONOCLINIC CELLS IN DEGREES (IF BEMIN= 0.0 DEFAULT= 90. DEGREES). BEMAX MAXIMUM BETA ANGLE FOR MONOCLINIC CELLS IN DEGREES (IF BEMAX= 0.0 DEFAULT= 125. DEGREES). CARD 4 WAVE,POIMOL,DENS,DELDEN FREE FORMAT WAVE WAVELENGTH IN ANGSTROMS (DEFAULT=0.0 IF CU K ALPHA1). POIMOL MOLECULAR WEIGHT OF ONE FORMULA UNIT IN A.M.U. (DEFAULT =0.0 IF FORMULA WEIGHT NOT KNOWN). DENS MEASURED DENSITY IN G CM(**-3) (DEFAULT =0.0 IF DENSITY NOT KNOWN). DELDEN ABSOLUTE ERROR IN MEASURED DENSITY. (DEFAULT =0.0 IF DENSITY NOT KNOWN). CARD 5 EPS,FOM,N_IMP,ZERO_S,ZERO_REF,OPTION FREE FORMAT EPS =0.0 THE ABSOLUTE ERROR ON EACH OBSERVED LINE IS TAKEN TO 0.03 DEG. 2THETA (DEFAULT VALUE) WHATEVER THE SPACING DATA TYPE (ITYPE IN CARD 2). =1.0 THE ABSOLUTE ERROR ON EACH OBSERVED LINE IS INPUT INDIVIDUALLY FROM CARD 6, AFTER THE OBSERVED 'D(I)' ON THE SAME LINE, ACCORDING TO THE SPACING DATA UNIT (e.g. 18.678 0.018 in deg. 2theta) EPS NE 0.0 AND 1.0 THE ABSOLUTE ERROR IS TAKEN AS A CONSTANT (= EPS),IN DEG. 2THETA, WHATEVER THE SPACING DATA TYPE (ITYPE IN CARD 2) (e.g. 0.02, which will apply to all input lines). FOM LOWER FIGURE OF MERIT M(N) REQUIRED FOR PRINTED SOLUTION(S) (DEFAULT=0.0 M(N)=10.0). N_IMP MAXIMUM NUMBER OF IMPURITY/SPURIOUS LINES ACCEPTED AMONG THE FIRST N LINES [N_IMP takes into account both impurity lines and peak positions out of the input absolute angular error EPS]. IF N_IMP <0 THE SEARCH STARTS WITH ZERO IMPURITY LINES, THEN, IT CONTINUES WITH ONE IMPURITY LINE, AND SO ON UNTIL 'N_IMP' IMPURITY LINES IS REACHED. ZERO_S A PRIORI SEARCH FOR A ZERO-POINT ERROR IN INPUT DATA. =0 NO SEARCH =1 SEARCH IF ZERO_S NE 0 OR 1, THEN ZERO_S REPRESENTS A KNOWN ZERO CORRECTION (e.g. -0.10) IN DEG. 2THETA. ZERO_REF =0 NO 'ZERO-POINT' LEAST-SQUARES REFINEMENT. =1 'ZERO-POINT' LEAST-SQUARES REFINEMENT. OPTION =0 DICVOL04 OPTION (OPTIMIZED STRATEGY SEARCH WITH DECREASING CELL VOLUMES). =1 OPTION WITH EXTENDED (EXHAUSTIVE) SEARCH IN VOLUME DOMAINS CONTAINING MATHEMATICAL SOLUTION(S) (LONGER CPU TIMES). IF OPTION IS OMITTED, DEFAULT IS DICVOL04. CARDS 6 to 6+N_TOTAL D(I) [,EPSIL(I)] FREE FORMAT (ONE FOR EACH INPUT LINE, FOR ALL N_TOTAL LINES) D(I) VALUE DESCRIBING THE OBSERVED POSITION OF LINE 'I' ACCORDING TO SPACING UNIT 'ITYPE'. EPSIL(I) ONLY IF EPS=1.0 (CARD 5): ABSOLUTE ERROR FOR 'D(I)', ACCORDING TO 'ITYPE', [IF EPS= 0.0 OR EPS IS A CONSTANT NOT EQUAL TO 1.0 (e.g. 0.02)(SEE CARD 5), ONLY 'D(I)' ARE REQUIRED]. NOTE: IF ITYPE=1,2,4 THE VALUES OF 'D(I)' AND 'EPSIL(I)' MUST BE PREFERABLY (THOUGH IT IS NOT MANDATORY) LISTED IN INCREASING ORDER. IF ITYPE=3 THEY MUST BE PREFERABLY LISTED IN DECREASING ORDER. ___________ OUPUT FILES ----------- DICVOL06 GENERATES TWO OUTPUT FILES: - A FILE CONTAINING THE SOLUTIONS AS FOUND BY THE PROGRAM (ALSO SEEN ON THE DISPLAY WHEN DICVOL06 IS RUNNING). - A SECOND FILE WITH THE SAME NAME AND THE EXTENSION '.ord', IN WHICH ALL (MATHEMATICAL) SOLUTIONS ARE RANKED ACCORDING TO THEIR de WOLFF FOM. ***************************************************** * * * THE USE OF DICVOL06 * * * ***************************************************** USE AS INPUT DATA ALL AVAILABLE DIFFRACTION LINES (N_TOTAL). ONLY THE FIRST N (eg 20, SEE CARD 2) LINES WILL BE USED FOR THE SEARCH OF SOLUTIONS. THESE SOLUTIONS ARE SUBSEQUENTLY USED AUTOMATICALLY FOR REVIEWING ALL N_TOTAL INPUT DATA. THE IMPURITY TOLERANCE 'N_IMP' IS RELATED ONLY TO THE N LINES USED FOR SEARCHING SOLUTION(S) (OF COURSE, OTHER UNINDEXED LINES CAN BE FOUND AMONG THE EXTRA INPUT LINES IN THE REVIEWING PROCESS). BE CAREFUL IN USING THE IMPURITY TOLERANCE: SPURIOUS LINES INCREASES THE RISK TO MISS THE CORRECT SOLUTION! ==> WITH GOOD QUALITY DATA, OPTION = 0 (i.e. DICVOL04) IS RECOMMENDED. ==>THE OPTION 'EXTENDED (EXHAUSTIVE) SEARCH' (OPTION =1 IN CARD 5), CAN BE USEFUL IN CASES OF (i) UNSTABLE CASES, i.e. MANY SOLUTIONS ARE FOUND IN A SMALL RANGE OF CELL VOLUMES, (ii) EXPECTED DIFFRACTION LINES ARE MISSING AMONG THE FIRST INPUT LINES, (iii) LOW QUALITY DATA, (iv) SIGNIFICANT NUMBER OF IMPURITY LINES, ETC. IF A SOLUTION IS FOUND IN A VOLUME SHELL, THE SEARCH IS EXHAUSTIVE WITHIN THIS SHELL. THUS, THE SEARCH IS NOT EXTENDED TO THE NEXT VOLUME SHELL (FOR THE SYMMETRY BEING ANALYSED). IF NEEDED, THE USER CAN RUN AGAIN DICVOL06, FOR SELECTED LATTICE SYSTEMS, TAKING THE HIGHER VOLUME VALUE OF THE ALREADY ANALYSED VOLUME SHELL AS 'VOLMIN' IN THE NEW INPUT PARAMETERS SET (CARD 3). GENERALLY, RUNS WITH OPTION =1 TAKE LONGER CPU TIMES AND THE NUMBER OF MATHEMATICAL SOLUTIONS IS GREATER (IT HAS BEEN LIMITED TO THE FIRST 100 FOUND SOLUTIONS IN THE DICVOL06 OUTPUT FILE). BY ACTING ON THE INPUT FOM (GREATER FOM IN CARD 5) SOLUTIONS WITH LOWEST FOMs CAN BE REJECTED). BE CAREFUL: AS SOON AS 100 SOLUTIONS ARE FOUND THE CALCULATION STOPS. DICVOL06 OFFERS THE POSSIBILITY TO ANALYSE YOUR INPUT DATA FOR THE PRESENCE OF A ZERO-POINT ERROR. THE METHOD EMPLOYED CAN SUGGEST MORE THAN ONE OR TWO SOLUTIONS (DUE TO UNCERTAINTY IN SEARCHING HARMONIC DIFFRACTION LINES). THIS OPTION IS TO BE USED PRIOR THE INDEXING PROCESS. PLEASE, AS FAR AS POSSIBLE AVOID THE USE OF THIS FACILITY BY ENSURING THE QUALITY OF YOUR COLLECTED DATA! USUAL 'ZERO-POINT' ERRORS (IF NOT TOO BIG) ARE GENERALLY CORRECTED BY THE LEAST-SQUARES REFINEMENT OF THE 'ZERO-POINT' PARAMETER (ZERO_REF IN CARD 5), TOGETHER WITH THE REFINEMENT OF CELL PARAMETERS. ZERO_REF IN CARD 5 IS, IN FACT, AN EXTRA DEGREE OF FREEDOM IN THE REFINEMENT. IT INCLUDES ALL SYSTEMATIC MEASUREMENT ERRORS FROM DIFFRERENT ORIGIN, E.G. ZERO-POINT SHIFT, SAMPLE-SURFACE DISPLACEMENT, UMBRELLA EFFECT, TRANSPARENCY, CAPILLARY DISPLACEMENT, .. SUGGESTED STRATEGY: ------------------ IT IS RECOMMENDED TO USE A TWO- [1 & 2] OR THREE-STAGES PROCEDURE (i.e. TRICLINIC LATTICES SHOULD PREFERABLY BE STUDIED SEPARATELY), e.g.: 1- SEARCH IN HIGH SYMMETRIES DOWN TO ORTHORHOMBIC. CARD 2 : N,ITYPE,1,1,1,1,0,0 2- SEARCH IN MONOCLINIC SYMMETRY. CARD 2 : N,ITYPE,0,0,0,0,1,0 3- IF NECESSARY, SEARCH IN TRICLINIC SYMMETRY. CARD 2 : N,ITYPE,0,0,0,0,0,1 NOTE THAT FOR SOLUTIONS WITH MONOCLINIC AND TRICLINIC SYMMETRIES THE PROGRAM PROVIDES THE REDUCED CELL. IF VARIOUS EQUIVALENT SOLUTIONS ARE FOUND, ONLY ONE OF THEM IS LISTED IN THE OUTPUT FILE. TRIGONAL SYMMETRY CASE WITH RHOMBOHEDRAL LATTICE: THE PATTERN IS INDEXED WITH AN HEXAGONAL LATTICE, HAVING A UNIT CELL VOLUME THREE TIMES GREATER. RECOMMENDATIONS --------------- READ CAREFULLY REFERENCES 1 AND 6 (AND 9), AS WELL AS THIS USER'S GUIDE. PLEASE, SPEND TIME TO ENSURE THE QUALITY OF YOUR COLLECTED DATA (SEE REF. 5). WITH ACCURATE DATA, THE SUCCESS RATE OF DICVOL06 IS VERY HIGH. PEAK POSITIONS SHOULD BE EXTRACTED WITH A PROFILE FITTING SOFTWARE. AN INTERACTIVE PROGRAM SHOULD BE PREFERRED, SINCE AUTOMATIC EXTRACTIONS CAN MISS LINES (LOW INTENSITY, SHOULDER, ..). WITH BAD DATA, THE CHANCE TO OBTAIN THE CORRECT SOLUTION IS SMALL AND THE CALCULATION CAN BE TIME-CONSUMING. WITH MODERN X-RAY POWDER DIFFRACTOMETERS (THE USE OF MONOCHROMATIC RADIATION IS RECOMMENDED), ABSOLUTE ERRORS ON PEAK POSITIONS LOWER THAN 0.02 DEGREES 2-THETA CAN BE ROUTINELY OBTAINED. FOR INDEXING PURPOSES, ERRORS SHOULD NOT (IDEALLY) EXCEED 0.03 DEG. 2-THETA. [IN EXCEPTIONAL CASES, A FEW LINES WITH GREATER INDIVIDUAL ESTIMATED ERROR CAN BE INTRODUCED IN THE INPUT DATA. IN THIS CASE, USE THE PARAMETER EPS= 1. IN CARD 5, AND ENTER INDIVIDUAL ERRORS AFTER D(I) FOR EACH LINE]. WITH HIGH RESOLUTION POWDER DIFFRACTION DATA (CONVENTIONAL OR, PARTICULARLY, SYNCHROTRON X-RAY SOURCES), THE ABSOLUTE ERROR IS USUALLY LESS THAN 0.02 (OR EVEN 0.01 WITH ULTRA-HIGH RESOLUTION) DEG. 2-THETA; CONSEQUENTLY, EPS=0.02 (OR EVEN EPS=0.01) IS RECOMMENDED; THE CONVERGENCE OF THE DICHOTOMY PROCEDURE WILL BE IMPROVED. HOWEVER, BE SURE THAT THIS CONDITION IS TRUE FOR ALL LINES USED AS INPUT DATA. (REMEMBER THAT ALL MATHEMATICAL SOLUTIONS WITHIN THE INPUT LIMITS AND ERROR BOUNDS ARE FOUND, THE GREATER THEY ARE THE GREATER IS THE NUMBER OF MATHEMATICAL SOLUTIONS). ===> N_IMP PARAMETER: N_IMP CAN BE USED IN CASE OF EXPECTED SPURIOUS LINES (i.e. IMPURITY LINES, AS WELL AS OBSERVED LINES OUT OF THE INPUT ERROR). N_IMP ACTS AT ALL SUCCESSIVE LEVELS OF THE DICHOTOMY ALGORITHM. AS SOON AS AN INDEXING SOLUTION IS RETAINED, A LEAST-SQUARES REFINEMENT OF LATTICE PARAMETERS IS CARRIED OUT. FOR THIS REFINEMENT A LARGER ERROR ON OBSERVED LINES IS CONSIDERED. THEN, A LINE REJECTED AT THE LAST DICHOTOMY LEVEL CAN, BY CHANCE, BE ACCEPTED WITH THE REFINED LATTICE PARAMETERS. [EXAMPLE OF POSSIBLE CASE: N_IMP = 0 NO SOLUTION; N_IMP = 1 ONE SOLUTION; HOWEVER, AFTER L-S REFINEMENT OF THE LATTICE PARAMETERS ALL N LINES USED FOR SEARCHING SOLUTIONS ARE INDEXED WITH THE REFINED PARAMETERS.] NOTE THAT THE PROGRAM DICVOL06 IS EXECUTABLE FROM 7 LINES- 8 LINES IF THE 'ZERO-SHIFT' IS REFINED - (THOUGH IT IS NOT RECOMMENDABLE SINCE L-S REFINEMENT UNSTABILITIES CAN BE EXPECTED). LONG AND SHORT AXIS CASES (DOMINANT ZONE CASES): IF SUCH CASES ARE EXPECTED, THE NUMBER 'N' OF LINES (CARD 2) USED FOR SEARCHING THE SOLUTION SHOULD, GENERALLY, BE GREATER THAN 20. THE MINIMUM VALUE FOR A LINEAR LATTICE PARAMETER HAS BEEN FIXED TO 2.5 ANGSTROMS. RELIABILITY OF INDEXING SOLUTIONS: READ PARAGRAPH 8 OF REF. 5 AND REFS 7 AND 8. THE BEHAVIOUR OF THE DICHOTOMY ALGORITHM WITH RESPECT TO THE NUMBER OF LINES REQUIRED FOR INDEXING AND THE CASE OF BIPHASIC MIXTURE IS DISCUSSED IN REF. 6. THE LOGICAL FILTERS USED IN DICVOL06 FOR THE SELECTION OF SOLUTIONS ARE DESCRIBED IN REF. 9. NOTE THAT WITH THE OPTION DICVOL04 (OPTION =0), AS SOON AS A SOLUTION IS FOUND, ONLY SOLUTIONS WITH SMALLEST VOLUMES WILL BE SUBSEQUENTLY RETAINED. IF (FOR SOME REASONS!) YOU ARE NOT SATISFIED BY THE SOLUTION, YOU CAN RUN AGAIN THE PROGRAM WITH AN INPUT LOWER VOLUME LIMIT SLIGHTLY GREATER THAN THAT OF THE FOUND SOLUTION (THE EXHAUSTIVE SEARCH IS THEN EXTENDED TO A HIGHER VOLUME). NOTE THAT THE SEARCH IS EXHAUSTIVE WITHIN THE LIMITS ON THE INPUT DATA. IN PARTICULAR, THE SEARCH IS CONSTRAINED BY THE HIGHER AND SMALLER BOUNDS ON PARAMETERS, VOLUMES, SELECTED FOM AND ABSOLUTE ERRORS ON PEAK POSITIONS. PLEASE ACT ON THESE PARAMETERS WHEN USING DICVOL06. A LATTICE METRIC SINGULARITY OCCURS WHEN UNIT CELLS DEFINING TWO LATTICES HAVE AN IDENTICAL SET OF CALCULATED d-SPACINGS. THIS CAN BE OBSERVED WITH HIGH SYMMETRY LATTICES (READ REF.5, SECT. 4.2, AND REFS THEREIN). SIMPLE RELATIONS EXIST BETWEEN THE PARAMETERS OF THE TWO CELLS, AS WELL AS PARTICULAR CELL-VOLUME RATIOS. A TYPICAL CASE IS: AN HEXAGONAL CELL [a, c, VOLUME V] CAN BE INDEXED WITH AN ORTHORHOMBIC CELL [PARAMETERS: a/2, a SQRT(3), c, VOLUME V/2]. DUE TO THE STRATEGY USED IN DICVOL, BASED ON AN ANALYSIS THROUGH DECREASING SYMMETRY, ALL CELLS SHOULD BE, IN PRINCIPLE, DISPLAYED IN THE OUTPUT FILE (EXCEPT IF A SOLUTION IS REJECTED BY THE INPUT MAXIMUM VOLUME). CHECK ON VALIDITY OF AN INDEXING RESULT: PLEASE READ REF. 5 (SECT. 8) POSSIBLE SPACE GROUPS: LOOK AT THE HKL CONDITIONS IN THE OUTPUT LIST OF THE REVIEWING OF THE COMPLETE INPUT DATA PROVIDED AFTER A SOLUTION IS FOUND FROM THE FIRST N LINES. ADDITIONAL INFORMATION ON DICVOL06 SHOULD APPEARED IN REF. 9. REFERENCES 1.- BOULTIF, A. AND LOUER, D., POWDER PATTERN INDEXING WITH THE SUCCESSIVE DICHOTOMY METHOD. J. APPL. CRYST. 37, 724-731 (2004). 2.- LOUER, D. AND LOUER, M., METHODE D'ESSAIS ET ERREURS POUR L'INDEXATION AUTOMATIQUE DES DIAGRAMMES DE POUDRE, J. APPL. CRYST. 5, 271-275 (1972). 3.- LOUER, D. AND VARGAS, R., INDEXATION AUTOMATIQUE DES DIAGRAMMES DE POUDRE PAR DICHOTOMIES SUCCESSIVES, J. APPL. CRYST. 15, 542-545, (1982). 4.- BOULTIF, A. AND LOUER, D., INDEXING OF POWDER DIFFRACTION PATTERNS FOR LOW SYMMETRY LATTICES BY THE SUCCESSIVE DICHOTOMY METHOD, J. APPL. CRYST. 24, 987-993 (1991). 5.- LOUER, D., AUTOMATIC INDEXING: PROCEDURES AND APPLICATIONS, IN 'ACCURACY IN POWDER DIFFRACTION II', NIST, SPEC. PUBL. No. 846, GAITHERSBURG, MD, USA, pp. 92-104, 1992. 6.- LOUER, D. AND BOULTIF, A., INDEXING WITH THE SUCCESSIVE DICHOTOMY METHOD, DICVOL04, Z. KRISTALLOGR. 23, 225-230 (2006). 7.- DE WOLFF, P.M., A SIMPLIFIED CRITERION FOR THE RELIABILITY OF A POWDER PATTERN INDEXING, J. APPL. CRYST. 5, 108-113 (1968). 8.- SMITH, G. S. AND SNYDER, R. L., F(N): A CRITERION FOR RATING POWDER DIFFRACTION PATTERNS AND EVALUATING THE RELIABILITY OF POWDER-PATTERN INDEXING, J. APPL. CRYST. 12, 60-65 (1979). 9.- LOUER, D. AND BOULTIF, A., POWDER PATTERN INDEXING AND THE DICHOTOMY ALGORITHM, Z. KRISTALLOGR., IN PRESS (2007).