MOLPRO

56 MATRIX OPERATIONS 389
memory,2,m
R = 0.96488518 ANG
THETA= 101.90140469
geometry={H1
O,H1,R;
H2,O,R,H1,THETA}
{hf;wf,10,1}
field=0.05
!define field strength
{matrop
load,h0,h0
!load one-electron hamiltonian
load,xx,oper,xx !load second moments
load,yy,oper,yy
load,zz,oper,zz
add,h01,h0,field,zz,-0.5*field,xx,-0.5*field,yy !add second moments to h0 and store in h01
save,h01,1210.1,h0} !save h0
hf
!do scf with modified h0
{matrop
load,h0,h0
!load h0
load,qmzz,oper,qmzz !load quadrupole moment qmzz
add,h01,h0,field,qmzz !add quadrupole moment to h0 (same result as above with second moments)
save,h01,1210.1,h0} !save h0
hf
!do scf with modified h0
quad,,,field
hf
!add quadrupole field to h0
!do scf with modified h0 (same result as above with matrop)
field,zz,field,xx,-0.5*field,yy,-0.5*field ! (add general field; same result as above)
hf
!do scf with modified h0 (same result as above with matrop)
field,zz,field !same as before with separate field commands
field+,xx,-0.5*field
field+,yy,-0.5*field
hf
!do scf with modified h0 (same result as above with matrop)
http://www.molpro.net/info/current/examples/matropfield.com
56.25 Exercise: SCF program
Write a closed-shell SCF program for H 2 O using MATROP!
Hints:
First generate a starting orbital guess by finding the eigenvectors of h0. Store the orbitals in a
record. Basis and geometry are defined in the usual way before the first call to MATROP.
Then use a MOLPRO DO loop and call MATROP for each iteration. Save the current energy in
a variable (note that the nuclear energy is stored in variable ENUC). Also, compute the dipole
moment in each iteration. At the end of the iteration perform a convergence test on the energy
change using the IF command. This must be done outside MATROP just before the ENDDO. At
this stage, you can also store the iteration numbers, energies, and dipole moments in arrays, and
print these after reaching convergence using TABLE. For the following geometry and basis set
geometry={o;h1,o,r;h2,o,r,h1,theta} !Z-matrix geometry input
r=1 ang !bond length
theta=104
!bond angle
basis=vdz
!basis set
thresh=1.d-8
!convergence threshold