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How I choose one suitable value of ppmfrq for a new system
Posted: Sat Dec 29, 2012 8:52 am
by gvtheen
Hi all,
In the GW calcualtion, how I choose one suitable value of ppmfrq for a new system?
thank you
gvtheen
Re: How I choose one suitable value of ppmfrq for a new syst
Posted: Sun Dec 30, 2012 10:37 am
by Chem
In the Plasmon Pole evaluation of the GW method, the second imaginary frequency may be taken from EELS.
Usualy it is of the order of 0.5 Hartree.
Good luck
Re: How I choose one suitable value of ppmfrq for a new syst
Posted: Fri Jan 04, 2013 3:59 am
by gabriel.antonius
The plasmon frequency computed from the electronic density makes sense mostly for metals and plasmas, where the electrons are completely free. Hence, you should ask "How many electrons in my system are actually free?" Count the electrons that form the open shells, or those that are the least bound, so you can estimate a "free electron density", and you get the plasma frequency from that density.
Cheers!