MOLPRO

5 INTRODUCTORY EXAMPLES 26
In the above example, the default basis set (VDZ) is used. We can modify the default basis using
a BASIS directive.
***,h2o cc-pVTZ basis !A title
r=1.85,theta=104
!set geometry parameters
geometry={O;
!z-matrix geometry input
H1,O,r;
H2,O,r,H1,theta}
basis=VTZ
!use VTZ basis
hf
!closed-shell scf
http://www.molpro.net/info/current/examples/h2o_scf_vtz.com
5.3 Geometry optimizations
Now we can also do a geometry optimization, simply by adding the card OPTG.
***,h2o
!A title
r=1.85,theta=104
!set geometry parameters
geometry={O;
!z-matrix geometry input
H1,O,r;
H2,O,r,H1,theta}
basis=6-31g**
!use Pople basis set
hf
!closed-shell scf
optg
!do scf geometry optimization
http://www.molpro.net/info/current/examples/h2o_scfopt_631g.com
5.4 CCSD(T)
The following job does a CCSD(T) calculation using a larger (VTZ) basis (this includes an f
function on oxygen and a d function on the hydrogens).
***,h2o
!A title
r=1.85,theta=104
!set geometry parameters
geometry={O;
!z-matrix geometry input
H1,O,r;
H2,O,r,H1,theta}
basis=VTZ
!use VTZ basis
hf
!closed-shell scf
ccsd(t)
!do ccsd(t) calculation
http://www.molpro.net/info/current/examples/h2o_ccsdt_vtz.com
5.5 CASSCF and MRCI
Perhaps you want to do a CASSCF and subsequent MRCI for comparison. The following uses
the full valence active space in the CASSCF and MRCI reference function.