[Pw_forum] temperature dependent density functional theory

[Hongsheng Zhao]

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