MOLPRO

55 ORBITAL MERGING 379
***,NO merge
r=2.1
symmetry,x,y
geometry={n}
!N-atom, c2v symmetry
{rhf;occ,3,1,1; !rhf nitrogen
wf,7,4,3;
!4S state
orbital,2110.2} !save orbitals to record 2110 on file 2
symmetry,x,y
geometry={o}
{rhf;occ,3,1,1; !rhf for oxygen
wf,8,4,2
!3P state
orbital,2120.2} !save orbitals to record 2120 on file 2
geometry={n;o,n,r}
! NO molecule, c2v symmetry
{MERGE
ORBITAL,2110.2 ! read orbitals of N atom
MOVE,1.1,1.1 ! move 1s orbital to output vector 1.1
MOVE,2.1,2.1,3.1 ! move 2s orbital to output vector 3.1
MOVE,3.1,3.1,5.1 ! move 2pz orbital to output vector 5.1
MOVE,1.2,1.2 ! move 2px orbital to output vector 1.2
MOVE,1.3,1.3 ! move 2py orbital to output vector 1.3
MOVE,4.1,,7.1 ! move virtual orbitals of symmetry 1
MOVE,2.2,,3.2 ! move virtual orbitals of symmetry 2
MOVE,2.3,,3.3 ! move virtual orbitals of symmetry 2
MOVE,1.4 ! move virtual orbitals of symmetry 2
ORBITAL,2120.2 ! read orbitals of O atom
MOVE,1.1,0.4
! move all oxygen orbitals into place
ROT,3.1,4.1,45; ! rotate 2s orbitals to make bonding and antibonding
! linear combinations
ROT,5.1,6.1,-45; ! rotate 2pz orbitals to make bonding and antibonding
! linear combinations
PRINT,1
! set print option
ORTH,6,2,2
! symmetrically orthonormalize the valence orbitals
! the resulting orbitals are printed
save,2150.2} ! save merged orbitals to record 2150.2
{multi;occ,6,2,2
wf,15,2,1
wf,15,3,1
start,2150.2}
! perform full valence casscf for NO
! 2Pix state
! 2Piy state
! start with merged orbitals
http://www.molpro.net/info/current/examples/no_merge1.com
One can also do the atomic calculations in the total basis set, using dummy cards. In this case
the procedure is more complicated, since the union of the two orbital spaces is over-complete.
The calculation can be done as follows:
a) SCF for the total molecule, orbitals saved to 2100.2
b) SCF for the N atom with dummy basis on the O atom, orbitals saved on 2110.2
c) SCF for the O atom with dummy basis on the N atom, orbitals saved on 2120.2
d) Merge the atomic SCF orbitals. Finally, obtain the virtual orbitals by projecting the merge
orbitals out of the SCF orbitals for NO.