## Firefly and PC GAMESS-related discussion club

Learn how to ask questions correctly

** Re^2: Can we calculate Frequency dependent dielectric constant of any sample? **
Siddheshwar Chopra

sidhusai@gmail.com

Dear Alex,

Thank you for the information. As per your input file, I ran the program to find polarizability of a molecule. I wish to ask that is it possible to give the FREQ(n) array for a range of 1MHz to 20GHz? Is it possible to get this frequency range in FIREFLY? Regards,

On Tue Jun 18 '13 8:02pm, Alex Granovsky wrote

----------------------------------------------

>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,

Wed Jun 19 '13 2:24pm

This message read **714** times