! EXAM 18.
!  diatomic P2...analytic hessian using effective core potential
!  See Stevens,Basch,Krauss, J.Chem.Phys. 81,6026-33(1984).
!  GAMESS FINAL E= -12.6956518722, with vibrational FREQ=913.17
!  A separate run gives E(P)= -6.32635, so De= 26.95 kcal/mol
!
 $CONTRL SCFTYP=RHF RUNTYP=HESSIAN PP=SBKJC NZVAR=1 $END
 $SYSTEM TIMLIM=1 $END
 $GUESS  GUESS=HUCKEL $END
 $ZMAT   IZMAT(1)=1,1,2 $END
 $DATA
diatomic phosphorous
Dnh 4
 
PHOSPHORUS 15.0   0.0000000000   0.0000000000   0.9393077548
   SBKJC
   D 1
     1 0.45 1.0
 
 $END

Link to the log file of this example.
exam18 Log File