C SUBROUTINE PREPOT C C System: IHI C Common name: no. A C Functional form: Extended-LEPS (London-Erying-Polyani-Sato) C Reference: C. A. Parr and D. G. Truhlar, C J. Chem. Phys., Vol. 75, 1844(1971). C C PREPOT must be called once before any calls to POT. C The potential parameters are included in the block data subprogram PTPACM. C Coordinates, potential energy, and derivatives are passed C The potential energy in the three asymptotic valleys are C stored in the common block ASYCM: C COMMON /ASYCM/ EASYAB, EASYBC, EASYAC C The potential energy in the AB valley, EASYAB, is equal to the potential C energy of the I "infinitely" far from the IH diatomic, with the C IH diatomic at its equilibrium configuration. Similarly, the terms C EASYBC and EASYAC represent the HI and the I2 asymptotic valleys, C respectively. C The other potential parameters are passed through the common blocks C SATOCM and LEPSCM. C All the information passed through the common blocks PT1CM, ASYCM, C SATOCM, and LEPSCM are in hartree atomic units. C C This potential is written such that: C R(1) = R(I-H) C R(2) = R(H-I) C R(3) = R(I-I) C The classical potential energy is set equal to zero for the I C infinitely far from the equilibrium HI diatomic. C C The flags that indicate what calculations should be carried out in C the potential routine are passed through the common block PT2CM: C where: C NASURF - which electronic states availalble C (1,1) = 1 as only gs state available C NDER = 0 => no derivatives should be calculated C NDER = 1 => calculate first derivatives C NFLAG - these integer values can be used to flag options C within the potential; C C C Potential parameters' default settings C Variable Default value C NDER 1 C NFLAG(18) 6 C IMPLICIT DOUBLE PRECISION (A-H,O-Z) C CHARACTER*75 REF(5) C PARAMETER (N3ATOM = 75) PARAMETER (ISURF = 5) PARAMETER (JSURF = ISURF*(ISURF+1)/2) PARAMETER (PI = 3.141592653589793D0) PARAMETER (NATOM = 25) C COMMON /PT3CM/ EZERO(ISURF+1) C COMMON/INFOCM/ CARTNU(NATOM,3),INDEXES(NATOM), + IRCTNT,NATOMS,ICARTR,MDER,MSURF,REF C C COMMON/USRICM/ CART(NATOM,3),ANUZERO, + NULBL(NATOM),NFLAG(20), + NASURF(ISURF+1,ISURF+1),NDER C COMMON /ASYCM/ EASYAB,EASYBC,EASYAC C COMMON /SATOCM/ DE(3), RE(3), BETA(3), Z(3) COMMON /LEPSCM/ ZPO(3), OP3Z(3), ZP3(3), TZP3(3), TOP3Z(3), * DO4Z(3), B(3) PARAMETER (CKCAL = 627.5095D0) PARAMETER (CANGS = 0.529177106D0) C C Echo the potential parameters C IF(NATOMS.GT.25) THEN WRITE(NFLAG(18),1111) 1111 FORMAT(2X,'STOP. NUMBER OF ATOMS EXCEEDS ARRAY DIMENSIONS') STOP END IF C WRITE (NFLAG(18), 100) DE, RE, BETA, Z C 100 FORMAT (/, 2X, T5, 'PREPOT has been called for IHI ', * 'potential surface A ', * /, 2X, T5, 'LEPS functional form', * //, 2X, T5, 'Potential energy surface parameters:', * /, 2X, T5, 'Bond', T47, 'I-H', T58, 'H-I', T69, 'I-I', * /, 2X, T5, 'Dissociation energies (kcal/mol):', * T44, F10.5, T55, F10.5, T66, F10.5, * /, 2X, T5, 'Equilibrium bond lengths (Angstroms):', * T44, F10.5, T55, F10.5, T66, F10.5, * /, 2X, T5, 'Morse beta parameters (Angstroms**-1):', * T44, F10.5, T55, F10.5, T66, F10.5, * /, 2X, T5, 'Sato parameters:', * T44, F10.5, T55, F10.5, T66, F10.5,/) C DO 10 I = 1,3 C C Convert to atomic units C DE(I) = DE(I)/CKCAL RE(I) = RE(I)/CANGS BETA(I) = BETA(I)*CANGS C C Compute useful constants C ZPO(I) = 1.0D0 + Z(I) OP3Z(I) = 1.0D0 + 3.0D0*Z(I) TOP3Z(I) = 2.0D0*OP3Z(I) ZP3(I) = Z(I) + 3.0D0 TZP3(I) = 2.0D0*ZP3(I) DO4Z(I) = DE(I)/4.0D0/ZPO(I) B(I) = BETA(I)*DO4Z(I)*2.0D0 10 CONTINUE C C Set the values of the classical energy in the three asymptotic valleys C EASYAB = DE(1) EASYBC = DE(2) EASYAC = DE(3) C C EZERO(1)=DE(2) C DO I=1,5 REF(I) = ' ' END DO C REF(1)='C. A. Parr and D. G. Truhlar' REF(2)='J. Chem. Phys. 75, 1844(1971).' C INDEXES(1) = 53 INDEXES(2) = 1 INDEXES(3) = 53 C C C IRCTNT=2 C CALL POTINFO C CALL ANCVRT C RETURN END C C***** C SUBROUTINE POT C C System: ABC C Functional form: Extended-LEPS (London-Erying-Polyani-Sato) C References: P. J. Kuntz, E. M. Nemeth, J. C. Polanyi, C S. D. Rosner, and C. E. Young C J. Chem. Phys. 44, 1168-1184 (1966) C C The potential parameters must be passed through the common blocks C PT1CM, ASYCM, PT2CM, SATOCM, and LEPSCM. C All information passed through the common blocks PT1CM, ASYCM, C SATOCM, and LEPSCM must be in Hartree atomic units. C C For the reaction: A + BC -> AB + C we write: C R(1) = R(A-B) C R(2) = R(B-C) C R(3) = R(C-A) C C NOTE: The potential energy at the reactant asymptote, that is at C A infinitely far from the BC diatomic, BC diatomic at its C equilibrium configuration, is set equal to zero. C IMPLICIT DOUBLE PRECISION (A-H,O-Z) C CHARACTER*75 REF(5) C PARAMETER (N3ATOM = 75) PARAMETER (ISURF = 5) PARAMETER (JSURF = ISURF*(ISURF+1)/2) PARAMETER (PI = 3.141592653589793D0) PARAMETER (NATOM = 25) C COMMON /PT1CM/ R(N3ATOM),ENGYGS,DEGSDR(N3ATOM) COMMON /PT3CM/ EZERO(ISURF+1) COMMON /PT4CM/ ENGYES(ISURF),DEESDR(N3ATOM,ISURF) COMMON /PT5CM/ ENGYIJ(JSURF),DEIJDR(N3ATOM,JSURF) C COMMON/INFOCM/ CARTNU(NATOM,3),INDEXES(NATOM), + IRCTNT,NATOMS,ICARTR,MDER,MSURF,REF C COMMON/USROCM/ PENGYGS,PENGYES(ISURF), + PENGYIJ(JSURF), + DGSCART(NATOM,3),DESCART(NATOM,3,ISURF), + DIJCART(NATOM,3,JSURF) C COMMON/USRICM/ CART(NATOM,3),ANUZERO, + NULBL(NATOM),NFLAG(20), + NASURF(ISURF+1,ISURF+1),NDER C COMMON /ASYCM/ EASYAB,EASYBC,EASYAC C COMMON /SATOCM/ DE(3), RE(3), BETA(3), Z(3) COMMON /LEPSCM/ ZPO(3), OP3Z(3), ZP3(3), TZP3(3), TOP3Z(3), * DO4Z(3), B(3) DIMENSION X(3), COUL(3), EXCH(3) PARAMETER (R2 = 1.41421356D0) C CALL CARTOU CALL CARTTOR C C Initialize the variable used in the calculation of the energy. C ENGYGS = 0.D0 C C Check the values of NASURF and NDER for validity. C IF (NASURF(1,1) .EQ. 0) THEN WRITE(NFLAG(18), 900) NASURF(1,1) STOP ENDIF IF (NDER .GT. 1) THEN WRITE (NFLAG(18), 910) NDER STOP 'POT 2' ENDIF C C Compute the energy. C DO 10 I = 1,3 X(I) = EXP(-BETA(I)*(R(I)-RE(I))) COUL(I) = DO4Z(I)*(ZP3(I)*X(I)-TOP3Z(I))*X(I) EXCH(I) = DO4Z(I)*(OP3Z(I)*X(I)-TZP3(I))*X(I) ENGYGS = ENGYGS + COUL(I) 10 CONTINUE C RAD = SQRT((EXCH(1)-EXCH(2))**2 + (EXCH(2)-EXCH(3))**2 + * (EXCH(3)-EXCH(1))**2) C ENGYGS = ENGYGS - RAD/R2 + EZERO(1) C C Compute the derivatives of the energy with C respect to the internal coordinates. C IF (NDER .EQ. 1) THEN S = EXCH(1) + EXCH(2) + EXCH(3) DO 20 I = 1,3 DEGSDR(I) = B(I)*X(I)*((3.0D0*EXCH(I)-S)/R2* * (OP3Z(I)*X(I)-ZP3(I))/RAD- * ZP3(I)*X(I)+OP3Z(I)) 20 CONTINUE ENDIF C 900 FORMAT(/,2X,T5,13HNASURF(1,1) =,I5, * /,2X,T5,24HThis value is unallowed. * /,2X,T5,31HOnly gs surface=>NASURF(1,1)=1 ) 910 FORMAT(/, 2X,'POT has been called with NDER = ',I5, * /, 2X, 'This value of NDER is not allowed in this ', * 'version of the potential.') C CALL EUNITZERO IF(NDER.NE.0) THEN CALL RTOCART CALL DEDCOU ENDIF C RETURN END C C***** C BLOCK DATA PTPACM IMPLICIT DOUBLE PRECISION (A-H,O-Z) C CHARACTER*75 REF(5) C PARAMETER (N3ATOM = 75) PARAMETER (ISURF = 5) PARAMETER (JSURF = ISURF*(ISURF+1)/2) PARAMETER (PI = 3.141592653589793D0) PARAMETER (NATOM = 25) C COMMON /PT3CM/ EZERO(ISURF+1) C COMMON/INFOCM/ CARTNU(NATOM,3),INDEXES(NATOM), + IRCTNT,NATOMS,ICARTR,MDER,MSURF,REF C C COMMON/USRICM/ CART(NATOM,3),ANUZERO, + NULBL(NATOM),NFLAG(20), + NASURF(ISURF+1,ISURF+1),NDER C COMMON /ASYCM/ EASYAB,EASYBC,EASYAC C COMMON /SATOCM/ DE(3), RE(3), BETA(3), Z(3) C C Initialize the flags and the I/O unit numbers for the potential C DATA NASURF /1,35*0/ DATA NDER /0/ DATA NFLAG /1,1,15*0,6,0,0/ C DATA ANUZERO /0.0D0/ DATA ICARTR,MSURF,MDER/3,0,1/ DATA NULBL /25*0/ DATA NATOMS /3/ C C Initialize the potential parameters; the energy parameters C kare in cal/mol, and the lengths are in Angstroms. C DATA DE/ 76.8D0, 76.8D0, 35.9D0/ DATA RE/ 1.6D0, 1.6D0, 2.67D0/ DATA BETA/ 1.75D0, 1.75D0, 1.86D0/ DATA Z/ 0.2D0, 0.2D0, 0.125D0/ C END C C*****