[Pw_forum] Re: cut-off radius for radial integrations (Paolo Giannozzi)

[Virginie Quequet]

Dear Paolo

Thank you very much for your replies. As you said, beyond 10 a.u. there
are only numerical noise, my problem was that my pseudo-potential had a 
big quantity of noise, so it changed the radial integration a lot.
The two pseudo-potential for Ti and Si, that I tried, were generated with 
FHIPP. I made some correction in order to eliminate this noise and now it
works fine when I change rcut.     

thanks a lot

Virginie Quequet


From: Paolo Giannozzi <giannozz at nest.sns.it>
Organization: Scuola Normale Superiore
To: pw_forum at pwscf.org
Subject: Re: [Pw_forum] Re: cut-off radius for radial integrations
Date: Tue, 22 Feb 2005 23:16:35 +0100
Reply-To: pw_forum at pwscf.org
On Thursday 17 February 2005 16:22, Virginie Quequet wrote:

> I try to change to 60 a.u. the cut-off radius for radial integration,

you shouldn't: the radial integration is performed on short-range
functions only. Beyond 10 a.u. all you have is numerical noise.

> which is put to 10 a.u. in the code (rcut variable). It seems to me 
> that it should change very little the results, but it is not the case.

please provide a test case (input and output) 

Paolo