# Example: Analytic Frequencies: CN¶

Download CN_SecDeriv.run

#! /bin/sh

# Calculation of normal modes is requested by specifying in the AMS input:
# Properties
#   NormalModes Yes
# End
# ADF will compute the Hessian analytically if possible.
# If the Hessian cannot be computed analytically, numerical differentiation
# will atuomatically be used.

# A good quality is specified for the numerical Becke integration to be sure of
# reliable results. In general, it seems advisable to use high accuracy for
# heavy nuclei at the moment, whereas default integration accuracy is usually
# sufficient for light atoms. The precision of the fit may be improved with the
# ZlmFit block keyword.

\$AMSBIN/ams <<eor
System
Symmetrize
atoms
N  -1.3  0.0   0.0
C   0.0  0.0   0.0
end
charge -1
end

Properties
NormalModes Yes
End

title CN
beckegrid
quality good
end
basis
type DZ
core None
CreateOutput Yes
end
xc
lda Xonly
end
EndEngine

eor