On Wednesday, October 28, 2015 04:13:41 PM 李睿 wrote: > Hello, everyone > I want to calculate molecules adsorption under 1Bar air pressure using > Pwscf. Can I add air pressure in it?
No, you cannot. Gas pressure is a macroscopic variable. It does not exist in a zero-temperature DFT calculation. You may do a molecular dynamics simulation with a bunch of molecules at a certain temperature, but it is very impractical and deducing the pressure from volume+temperature when the volume is so small and includes a chemically reactive surface is not granted. What you can do is to include its effect via a chemical potential, you can find a brief explanation in chapter 3.2 of my PhD thesis <http://urania.sissa.it/xmlui/bitstream/handle/1963/5363/paulatto_thesis.pdf?sequence=1&isAllowed=y> (eq. 3.12 in particular, but read all the chapter). If I remember correctly, I studied the problem on "Arthur W. Adamson, Physical Chemistry of Surfaces, John Wiley and Sons, 1990", so if you can get a copy of the book you'll find a better and longer explanation. HTH -- Dr. Lorenzo Paulatto IdR @ IMPMC -- CNRS & Université Paris 6 +33 (0)1 44 275 084 / skype: paulatz http://www.impmc.upmc.fr/~paulatto/ 23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05 _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
