# Example: Analytic Frequencies: CN¶

Download CN_SecDeriv.run

#! /bin/sh

# Calculation of analytical second derivatives is requested by specifying:
#   AnalyticalFreq
#   End
# in the ADF input.

# 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.

title CN

atoms
N  -1.3  0.0   0.0
C   0.0  0.0   0.0
end

Basis
Type DZ
Core None
End

charge -1

XC
LDA Xonly
End

BeckeGrid
quality good
End

AnalyticalFreq
End

eor

mv TAPE21 CN.t21
rm -f logfile

# After SCF is completed, the energy second derivatives matrix is calculated and
# analysed, which yields in this case one frequency.