! EXAM 42.
! numerical gradient for CN, using open shell CC(2,3).
!
! This tests the numerical gradient driver, and also
! emphasizes that the Dunning correlation consistent
! basis sets should be used in spherical harmonic form.
!
! A numerical gradient computation requires the energy
! at the molecule's actual geometry, plus energies at
! a pair of geometries displaced along each of its
! totally symmetric directions.
! A diatomic has 1 totally symmetric degree of freedom,
! so this run requires 3 energies for 1 gradient.
!
! See METHOD=FULLNUM in $FORCE for numerical hessians,
! and RUNTYP=FFIELD for numerical polarizabilities.
!
! There are 30 AOs, 28 MOs, 2 frozen cores, so 5 alpha
! and 4 beta valence electrons are correlated.
!
! E(ROHF)= -92.1960778308, E(CCSD)= -92.4767618032,
! the CR-CCL energy E(CC(2,3)) = -92.4930167395,
! and RMS gradient= 0.026601131 at the CC(2,3) level.
! (will optimize to -92.4941853332 at 1.1966876)
!
$contrl scftyp=rohf cctyp=cr-ccl mult=2 nzvar=1
runtyp=gradient numgrd=.true. ispher=1 $end
$system timlim=4 $end
$basis gbasis=ccd $end
$zmat izmat(1)=1,1,2 $end
$ccinp maxcc=50 $end
$data
CN...experimental geometry...X-2-sigma-plus state
Cnv 4
C 6.0 0.0 0.0 0.0
N 7.0 0.0 0.0 1.1718
$end

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Link to the log file of this example.

exam42 Log File

created on 6/20/2013