On Friday, June 5, 2009 at 23:18, akohlmey at cmm.chem.upenn.edu wrote: >> > what "Temperature dependent DFT" would encompass. >> >> In my mind, all the first principles/ab initio calculations only work >> under 0K, so I want to know whether can I do the first principles/ab >> initio calculations under other temperatures other than 0K, especially >> under some temperatures around room temperature?
> first of all, the way people talk about ab initio being calculations > at OK usually has to be seen in the context of geometry optimizations. > this approach generally uses the time independent DFT formalism and > thus the Born-Oppenheimer approximation and with in that approximation > you can very well do molecular dynamics, i.e. a system at temperature > different from OK. you can do this with pw.x but also in cp.x using > the car-parrinello hamiltonian. > of course there is the effect of temperature to the electronic > structure, but that is is generally very small, unless you go > to very high temperatures. this can be treated as well, but require > some more complicated to use methods. in most cases, you should be > just fine by applying a finite temperature to your atoms and using > normal DFT. By what means/parameters can I apply a finite temperature to my system? Kind regards, -- Hongsheng Zhao <zhaohscas at yahoo.com.cn> Xinjiang Technical Institute of Physics and Chemistry Chinese Academy of Sciences GnuPG DSA: 0xD108493 2009-6-6
