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           !add quadrupole field to h0
hf                     !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)