MOLPRO

19 THE MCSCF PROGRAM MULTI 139
of the C 2v calculation as reference for all other calculations. In this case one would have to take
out the second-last input card, which sets reforb=2141.2.
***,H2S diabatic A" states
basis=VDZ
symmetry,x,planeyz
orient,noorient
geometry={s;h1,s,r1;h2,s,r2,h1,theta}
gprint,orbitals,civector
text,reference calculation for C2V
theta=92.12,r1=2.3,r2=2.3
{hf;occ,7,2;wf,18,1}
!use cc-pVDZ basis set
!use Cs symmetry & fix orientation of the molecule
!dont allow automatic reorientation
!Z-matrix geometry input
!global print options
!reference geometry
!scf calculation for ground state
{multi;occ,9,2;closed,4,1;
!define active and inactive spaces
wf,18,2;state,2;
!two A" states (1B1 and 1A2 in C2v)
orbital,2140.2} !save orbitals to 2140.2
reforb=2140.2
text,calculations at displaced geometries
rd=[2.4,2.5,2.6]
do i=1,#rd
r2=rd(i)
{multi;occ,9,2;closed,4,1;
wf,18,2;state,2;
orbital,2141.2
diab,reforb}
reforb=2141.2
enddo
!define a range of bond distances
!loop over displaced geometries
!set r2 to current distance
!same wavefunction definition as at reference geom.
!save new orbitals to record
!compute diabatic orbitals using reference orbitals
!stored on record reforb
!set variable reforb to the new orbitals.
http://www.molpro.net/info/current/examples/h2s_diab.com
See section 38 for the automatic generation of diabatic energies.
19.6 Selecting the optimization methods
By default, MULTI uses the non-linear optimization method developed by Werner, Meyer, and
Knowles. Other methods, such as the Newton-Raphson procedure or the Augmented Hessian
procedure, are also implemented and can be selected using the ITERATIONS directive (for
state-averaged calculations, only the non-linear optimization method can be used). For CASSCF
calculations, the CI problem is solved in a basis of Slater determinants, unless a CONFIG card
is given. Some procedures may be disabled using the DONT directive.
19.6.1 Selecting the CI method
CONFIG,key;
key may be DET or CSF, and defaults to CSF. If no CONFIG or SELECT card is given, the
default is determinants (CASSCF).