! EXAM23.
!   semiempirical calculation, using the MOPAC/GAMESS combo
!   AM1 gets the geometry disasterously wrong!
!
!   initial geometry,            MNDO       AM1         PM3
!   HEAT OF FORMATION         105.14088   93.45997   46.89387
!   RMS gradient              0.0818157  0.1008587  0.0366232
!   optimized geometry (# steps),   8         10         7 
!   HEAT OF FORMATION          46.45648   -1.81730   -2.79646
!   RMS gradient              0.0000063  0.0000062  0.0000187
!   r(SiH)                      1.42108    1.45806    1.52101
!   a(HSiH)                     101.956    120.000     96.298
!
!   At the optimized PM3 geometry, the charge on Si= -.4681,
!   and the dipole moment is 2.346 Debye.
!
 $CONTRL SCFTYP=RHF RUNTYP=OPTIMIZE COORD=ZMT ICHARG=-1 $END
 $SYSTEM TIMLIM=1 $END
 $BASIS  GBASIS=PM3 $END
 $DATA
Silyl anion...comparison of semiempirical models
Cnv 3

Si
H  1  rSiH
H  1  rSiH  2 aHSiH
H  1  rSiH  2 aHSiH  3   aHSiH  -1

rSiH=1.15
aHSiH=110.0
 $END