Example: CV(n)-DFT excitation energies: Formamide¶

Download Formamide_CVnDFT.run

Calculation of the excitation energies of Formamide using the CV(n)-DFT method. Due to bugs in older versions it is important to use ADF2016.105 or later.

Example of CV($$\infty$$)-DFT where the molecular orbitals for the particular excitation are optimized (relaxed), which is called the R-CV($$\infty$$)-DFT method. In this case, the transition U-vector is frozen, while the orbitals are relaxed. ALLPOINTS should be used in case of a symmetric molecule. EXACTDENSITY should be used for precision reasons. Note that the irrep labels for C(s) symmetry that are used in the excitation code (A’ and A’‘) differ from those that are used during the SCF (AA and AAA). The example contains of 2 parts. In the first example singlet-singlet excitations are calculated using the subkeyword ONLYSING in the EXCITATIONS block key. In the second example singlet-triplet excitations are calculated replacing the subkeyword ONLYSING with the subkeyword ONLYTRIP in the EXCITATIONS block key.

\$ADFBIN/adf <<eor
Title Formamide
basis
Type DZ
Core None
end
Numericalquality good
atoms
H -0.927427 -0.600301 0.000000
H  1.070498 -1.782390 0.000000
H  2.024514 -0.325050 0.000000
C  0.000000  0.000000 0.000000
O  0.000000  1.225060 0.000000
N  1.119392 -0.775069 0.000000
end
allpoints
xc
hybrid B3LYP
end
CVnDFT
ITERATION 10
TOLERANCE 0.001
R_CV_DFT &
RELAXALPHA 1
RELAXBETA 1
DAMPORBRELAX 0.2
SUBEND
END
TDA
EXACTDENSITY
EXCITATION
Davidson &
A' 2
A'' 2
SUBEND
lowest 4
ONLYSING
ANALYTICAL
TOLERANCE 1e-5
END
end input
eor