The ABINIT Users Mailing List ( CLOSED )

["Narayani Choudhury" <n.choudhury@gl.ciw.edu>]

-------- Original Message --------
Subject: Re: Pressure Convergence
From: Xavier Gonze <gonze@pcpm.ucl.ac.be>
Date: Sat, February 21, 2004 10:49 am
To: n.choudhury@gl.ciw.edu

Dear Narayani Choudhury,

Narayani Choudhury wrote:
> Dear Xavier,
>
> I have used ABINIT for studies with P (both bulk and uniaxial).
>
> (i) Recently, at a conference I heard that
> ABINIT does not incoporate finite basis set correction to the stress
> tensor as for eg. in CASTEP.

This is wrong : as mentioned in the tutorial, and in the description of
the "optcell" variable,
one can use a non-zero value of the input variable "ecutsm" (0.5 Ha is
fine) to incorporate them.

One might, alternatively
use the "dedlnn" input variable, but this correction is less automatic
than the one provided by "optcell".

I realize that the description of the "ecutsm" input variable is
somewhat obscure. This will be changed in the next release of ABINIT.


> I find the stress tensor to be very sensitive to both ecut and k-pt
> and its convergence is quite difficult. I recently had a problem in
> agreement of ABINIT with calculations using PWSCF, but by increasing
> the ecut  and k-pts, I could resolve that. Are there plans to put
> these basis set corrections in?


> Thanks in advance! I really like ABINIT and wish you every success,
Thank you very much for the appreciation of the work !

Best regards,
Xavier

> Narayani
------------------------------------------
Narayani Choudhury
Geophysical laboratory,
Carnegie Institution of Washington,
5251, Broad Branch Road, N.W.,
Washington D.C. 20015
Phone: +1-202-478-8945
email: n.choudhury@gl.ciw.edu