MOLPRO

37 NON ADIABATIC COUPLING MATRIX ELEMENTS 273
***,lif non-adiabatic coupling
memory,1,m
basis,f=avdz,li=vdz
r=[10.0,10.5,11.0,11.5,12.0]
dr=0.01
geometry={li;f,li,rlif}
!define basis
!define bond distances
!define increment
!define geometry
rlif=3 !first calculation at R=3
{hf;occ,4,1,1}
!SCF
{multi;closed,3;
!CASSCF, 3 inactive orbitals
wf,12,1;state,2;
!Two 1A1 states
orbital,2140.2} !dump orbitals to record 2140.2
do i=1,#r
rlif=r(i)
{multi;closed,3;
wf,12,1;state,2;
orbital,2140.2}
!loop over geometries
!set bond distance
!CASSCF, 3 inactive orbitals
!Two 1A1 states
!Overwrite previous orbitals by present ones
{ci;state,2;noexc;
!CI for 2 states, no excitations
save,6000.2; !save wavefunction to record 6000.2
dm,8000.2} !save (transition) densities to record 8000.2
rlif=r(i)+dr
!increment bond distance by dr
{multi;closed,3;
!same CASSCF as above
wf,12,1;state,2;
!Two 1A1 states
start,2140.2;
!start with orbitals from reference geometry
orbital,2141.2; !save orbitals to record 2141.2
diab,2140.2}
!generate diabatic orbitals by maximizing the
!overlap with the orbitals at the reference geometry
{ci;state,2;noexc;save,6001.2} !CI for 2 states, wavefunction saved to record 6001.2
{ci;trans,6000.2,6001.2; !Compute overlap and transition density
dm,8100.2} !Save transition density to record 8100.2
rlif=r(i)-dr
!repeat at r-dr
{multi;closed,3;
!same CASSCF as above
wf,12,1;state,2;
!Two 1A1 states
start,2140.2;
!start with orbitals from reference geometry
orbital,2142.2; !save orbitals to record 2142.2
diab,2140.2}
!generate diabatic orbitals by maximizing the
!overlap with the orbitals at the reference geometry
{ci;state,2;noexc;save,6002.2} !CI for 2 states, wavefunction saved to record 6002.2
{ci;trans,6000.2,6002.2; !Compute overlap and transition density
dm,8200.2} !Save transition density to record 8200.2
{ddr,dr,2140.2,2141.2,8100.2}
nacme1p(i)=nacme
{ddr,-dr,2140.2,2142.2,8200.2}
nacme1m(i)=nacme
{ddr,2*dr
orbital,2140.2,2141.2,2142.2;
density,8000.2,8100.2,8200.2}
nacme2(i)=nacme
end do
!compute NACME using 2-point formula (forward difference)
!store result in variable nacme1p
!compute NACME using 2-point formula (backward difference)
!store result in variable nacme1m
!compute NACME using 3-point formula
!orbital records for R, R+DR, R-DR
!transition density records for R, R+DR, R-DR
!store result in variable nacme2
!end of loop over differend bond distances
nacmeav=(nacme1p+nacme1m)*0.5 !average the two results forward and backward differences
table,r,nacme1p,nacme1m,nacmeav,nacme2 !print a table with results
title,Non-adiabatic couplings for LiF !title for table
http://www.molpro.net/info/current/examples/lif_nacme.com