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