The ABINIT Users Mailing List ( CLOSED )

[Stephane BECU <stephane.becu@st.com>]

Abinit computes the electronic dielectric tensor via a linear response
calculation (2nd derivative of the energy) from DFPT. It also computes the
static dielectric tensor (at finite frequencies ie the ionic part of the
dielectric tensor) and the ELECTONIC NON-LINEAR susceptibilities via a
non-linear response calculation (3rd derivative of the energy) from DFPT.
What I am interested in are the STATIC NON-LINEAR susceptibilities (at
finite frequencies). In fact I think it is not available from DFPT with
abinit, but I think it could be possible to calculate them from a Berry
phase calculation. Am I right?

Stéphane

-----Original Message-----
From: Anglade Pierre-Matthieu [mailto:anglade@gmail.com] 
Sent: Monday, August 07, 2006 9:11 AM
To: forum@abinit.org
Subject: Re: [abinit-forum] NON-LINEAR SUSCEPTIBILITIES


I really don't know (answere for each of your questions). Yet since no one
has answered your first question after three days I guess that it means that
this is not done within abinit. In fact I'm just wondering about what you
mean by "nonlinear" susceptibilities ? What's the difference between this
and the susceptibility matrix computed within abinit ? Would you mind
teaching me (if this can be done in a few
words) about this ?

PMA

On 8/7/06, Stephane BECU <stephane.becu@st.com> wrote:
> Hi Pierre-Matthieu,
>
> Do you mean that such equations have to be implemented in the ABINIT 
> code? Do you know if the other existing ab-initio  packages (e.g. the 
> Vienna ab-initio simulation package VASP or any other one) have ever 
> done such calculations?
>
> Thanks again for your help
>
> Stéphane
> -----Original Message-----
> From: Anglade Pierre-Matthieu [mailto:anglade@gmail.com]
> Sent: Monday, August 07, 2006 8:34 AM
> To: forum@abinit.org
> Subject: Re: [abinit-forum] NON-LINEAR SUSCEPTIBILITIES
>
>
> Hi,
>
> If you have a formula for this kind of thing, since abinit is GPL, you 
> can do it :-)
>
> regards
>
> PMA
>
> On 8/4/06, Stephane BECU <stephane.becu@st.com> wrote:
> > Dear all,
> >
> > Do you if it is possible to compute non-linear susceptibilities at 
> > finite frequencies with abinit?
> >
> > Thanks for your help,
> >
> > Stéphane Bécu
> >
> >
>
>
>
>


-- 
Pierre-Matthieu Anglade