# Example: Excited state geometry optimization with a constraint: CH2O¶

Download EGO_CH2O_trip_constr.run

#!/bin/sh

# Example for an excited triplet state geometry optimization with a constraint
# included.

# Needed for such excited state optimizations are the key EXCITATIONS (to
# calculate excitation energies), the key GEOMETRY (to do a geometry
# optimization) and the key EXCITEDGO (to select for which excitation a geometry
# optimization should be performed). In this case a Z-matrix input for the
# coordinates is used, and a constraint is used using the GEOVAR keyword. Note
# that one has to select the state with the irrep name A'', and not with AAA.

atoms zmatrix
C         0 0 0       0.0      0.0      0.0
O         1 0 0       R        0.0      0.0
H         1 2 0       1.0    110.0      0.0
H         1 2 3       1.0    110.0    170.0
end

XC
END

GEOVAR
R=1.2 F
END

GEOMETRY
END

BASIS
TYPE DZ
CORE NONE
end

excitations
davidson
End
LOWEST 5
onlytrip
end

EXCITEDGO
STATE A'' 1
TRIPLET
OUTPUT 2
end

SYMMETRY C(S)

eor