Example: Resonance Raman, excited state gradient: Uracil¶
Example shows a calculation of the Resonance Raman spectrum (RRS) of uracil. In this example the RRS is calculated using the excited-state gradient.
A frequency restart file ‘restart.freq.t21’ is used as input in the resonance Raman calculation. This restart file is the TAPE21 of a numerical frequency calculation, that uses Cartesian displacements. First the frequency calculation is performed.
Next the resonance Raman calculation is performed by setting the ‘VIBRON’ subkey in the ‘GEOMETRY’ block key, including both the ‘EXCITATION’ block key and the ‘VIBRON’ block key. These are the only differences with the frequency run where only the ‘FREQUENCIES’ subkey was set in the ‘GEOMETRY’ block key, and the ‘EXCITATION’ and ‘VIBRON’ block key were not set.
$ADFBIN/adf << eor
Title Input generated by modco
EPRINT
SFO NOEIG NOOVL NOORBPOP
SCF NOPOP
END
NOPRINT BAS FUNCTIONS
UNITS
length angstrom
angle degree
END
ATOMS
N -0.0147481688 -0.0251586720 0.0000000000
C -0.0263429706 1.3809974655 0.0000000000
N 1.2556533768 1.9305098959 0.0000000000
C 2.5041083561 1.2440596334 0.0000000000
C 2.3755611578 -0.2074475201 0.0000000000
C 1.1446314693 -0.7882184482 0.0000000000
H -0.9346804118 -0.4675883900 0.0000000000
O -1.0845317554 2.0515533614 0.0000000000
H 1.3029888073 2.9549419374 0.0000000000
O 3.5819185026 1.8899458170 0.0000000000
H 3.2859343437 -0.7987226158 0.0000000000
H 0.9976482662 -1.8650665505 0.0000000000
END
BASIS
type DZ
core NONE
END
XC
GGA Becke88 Perdew86
END
SYMMETRY tol=0.001
GEOMETRY
VIBRON
END
SCF
iterations 50
converge 1.0e-6 1.0e-6
mixing 0.2
lshift 0.0
diis n=10 ok=0.5 cyc=5 cx=5.0 cxx=10.0
END
EXCITATION
ONLYSING
LOWEST 5
END
MBLOCKBIG
VIBRON
NMTAPE restart.freq
RESRAMAN
STPSIZ 0.1
DOMODES 11 13 16 17
DSCHEME ELCHAR
END
END INPUT
Note that used basis set is too small to get accurate results.