Well, as a matter of fact you could try to use the quantum-enthalpy
functional of Matteo Cococcioni et al. Phys. Rev. Lett. *94*, 145501
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.94.145501
Please double check that this is something that may be useful for your
calculations. In case, the method is implemented in the CP code,
PRESS_AI namelist, but also in PW by exploiting the external Environ
module (which you would need to download and compile, more details can
be found here www.quantum-environment.org). The actual release of
Environ is compatible with QE 5.1, 5.1.1 and 5.1.2, if you are using a
more recent version I could let you have the patch.
Oliviero Andreussi
Senior Postdoctoral Researcher
École Polytechnique Fédérale de Lausanne (EPFL) and
Università della Svizzera Italiana (USI) of Lugano
Switzerland
On 10/28/2015 10:05 AM, Lorenzo Paulatto wrote:
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
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