[Pw_forum] How to set the ensemble when doing MD

[Nicola Marzari]

Lu Yunhao wrote:
> Sorry, my questions are somewhat confused. I just want to compare MD
> calculations at different temperatures under Electric Field.  I am also
> interested in what will happen if the total energy is constant (NVE). Do you
> have some experience on this?



Dear Lu,


one comment - I suspect that the electric fields you need to
apply in order to see some effects on these small cell sizes
and time scales need to be huge and unphysical. Maybe not -
probably the best references would be looking at some ab-initio
MD done by Pasquarello (I believe on HCl) and later by Car and
Sharma, with the goal in mind of calculating the static limit
of the dielectric constant (i.e. to take into account, in a liquid,
also of the ionic screening).

			nicola

---------------------------------------------------------------------
Prof Nicola Marzari   Department of Materials Science and Engineering
13-5066   MIT   77 Massachusetts Avenue   Cambridge MA 02139-4307 USA
tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu