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Re: Can we calculate Frequency dependent dielectric constant of any sample?

Alex Granovsky
gran@classic.chem.msu.su

Dear Siddheshwar,

dielectric constant is a macroscopic property.
At microscopic level, we can compute frequency-dependent
polarizabilities and hyper-polarizabilities. Having a certain
model of the macroscopic body one can relate a microscopic
properties such as polarizability to a dielectric constant.

Below please find a sample file with computation of
frequency-dependent polarizability for benzene molecule
using PBE0 density functional. In brief, this is done
using runtyp=TDHF and specifying some DFTTYP.
If no DFTTYP is given, then these are indeed classical
TDHF calculations, if DFTTYP is given then they in fact
become TDDFT computations.

``` \$CONTRL SCFTYP=RHF DFTTYP=PBE0 runtyp=TDHF nosym=1 \$END
\$SYSTEM TIMLIM=300 MEMORY=3000000 \$END
\$BASIS  GBASIS=N31 NGAUSS=6 NDFUNC=1 NPFUNC=1 \$END
\$TDHF NFREQ=2 FREQ(1)=0,0.1 \$END
\$DATA
C6H6
Dnh       6

CARBON      6.0     -0.698164472         1.209256337         0.000000000
HYDROGEN    1.0     -1.241338149         2.150060743         0.000000000
\$END
```

Kind regards,
Alex Granovsky

On Fri Jun 14 '13 11:00am, Siddheshwar Chopra wrote
---------------------------------------------------
>Dear Sir,
>I would be glad if you could throw some light on How to calculate the frequency dependent Dielectric constant using FIREFLY?? As far as I have read, DFPT is used to do the same... please help.

>Regards,

Tue Jun 18 '13 8:02pm