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Re^7: Is it possible to get UV-VISIBLE AND RAMAN SPECTRUM USING FIREFLY???

Thomas
thomaspijper@hotmail.com


Dear Siddehshwar,

Below is a very basic input example for a TDDFT calculation on butadiene. Note that it lacks a few groups and keywords that one would normally use in a multiprocessor environment, such as the $P2P group. If you would like to run a CIS or TDHF calculation, you should change the value of CITYP to CIS or TDHF and remove the DFTTYP variable. Also, you should change the name of the $TDDFT group to $CIS or $TDHF (keywords for these groups are the same).

$CONTRL CITYP=TDDFT DFTTYP=PBE0 RUNTYP=ENERGY $END
$SYSTEM TIMLIM=525600 MEMORY=10000000 $END
$BASIS GBASIS=N31 NGAUSS=6 NDFUNC=1 $END
$TDDFT NSTATE=4 ISTSYM=0 ISTATE=1 $END
$DATA 1,3-butadiene TDDFT/6-31G(d)//RHF/6-31G(d)
CNH 2
C 6.0 0.5262888328 0.5113710450 0.0000000000
C 6.0 1.8213687868 0.2431548398 0.0000000000
H 1.0 0.1953148875 1.5374180614 0.0000000000
H 1.0 2.5595257633 1.0243655101 0.0000000000
63
H 1.0 2.1906083178 -0.7681578804 0.0000000000
$END

Right now, not all available XC functionals can be used for TDDFT calculations. The following functionals can be used only:

SLATER VWN1RPA SVWN1RPA B1LYP B88 VWN5 BVWN1RPA BHHLYP XPW91 PW91LDA SVWN5 B1PW91 GILL96 LYP BVWN5 B3PW91 XPBE96 CPW91 SLYP B3LYP1 OPTX CPBE96 BLYP B3LYP5 GLYP O3LYP1 OLYP O3LYP5 XLYP X3LYP BPW91 PBE1PW91PW91 PBE0 PBEPW91 PBE96

Finally, I should mention that it is possible to request the Tamm-Dancoff approximation to TDDFT by specifying

$TDDFT TDA=.T. $END

In the output, you can find excitation energies and oscillator strengths which can be used to plot the UV/vis spectrum. Useful programs for plotting the UV/vis spectrum are GaussSum (freeware) and ChemCraft.

Hope this helps.


Kind regards,
Thom


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