SYMMETRY gnorm=0 PRECISE
  Formaldehyde, for Demonstration Purposes
       
  O
  C 1.2 1
  H 1.1 1 120 1
  H 1.1 0 120 0 180 0 2 1 3
 
  3 1 4
  3 2 4
 
 oldgeo force isotope
   Do a force calculation on previous geometry
 
 oldgeo am1 nllsq gnorm=0 DERIV DEBUG DCART
   Calculate the AM1 geometry, starting with the MNDO optimized geometry
 
 oldgeo force  AM1
   Do a FORCE calculation on the AM1 geometry
 
 oldgeo restart force 
   Re-do the FORCE calculation using the MNDO hessian
 
 oldgeo pm3  ef gnorm=0
   Calculate the PM3 geometry, starting with the AM1 geometry
 
 oldgeo force  PM3
  Do a FORCE calculation on the PM3 geometry
 
    charge=1
  Formaldehyde, for Demonstration Purposes
       
  O
  C 1.2 1
  H 1.1 1 120 1
  H 1.2 1 120 1 150 1 2 1 3
 
  oldgeo force  CHARGE=1
   FORCE calculation on CH2O(+), RHF
 
 oldgeo uhf  CHARGE=1
   Optimize the CH2O(+) geometry, UHF, starting with RHF geometry
 
 oldgeo force CHARGE=1 uhf
  Do a force calculation on UHF geometry.
 
    charge=1 T=1M DUMP=1 UHF
  Formaldehyde, for Demonstration Purposes
       
  O
  C 1.2 1
  H 1.1 1 120 1
  H 1.2 1 120 1 150 1 2 1 3
 
  oldgeo force CHARGE=1 t=1h dump=23m
   RHF force calculation
 
 oldgeo uhf RESTART CHARGE=1  t=1h
 Restart geometry optimization in UHF
 
 oldgeo force CHARGE=1  uhf