[CP2K:8838] Ab - initio MD of pure sodium

Aniruddha Dive anirudd... at gmail.com
Thu Mar 23 18:19:31 CET 2017

Thanks Juerg,

I shall try using Fermi smearing and diagonalization. Also I want to run a 
separate simulation for a sodium glass, in that case also do I need to use 
fermi smearing and diagonalization methods or is it the case only where 
pure metal is involved. I have a system where I have a pure sodium metal 
and glass containing sodium ions in contact. Should those be treated in the 
same way?

Thanks and Regards,
Aniruddha M Dive

On Thursday, March 23, 2017 at 2:31:56 AM UTC-7, jgh wrote:
> Hi 
> you are attempting a 0 K electronic structure calculation of 
> a metal. There is a good chance that you are simulating an 
> excited state. 
> Not using the Mermin functional (with Fermi smearing) for a metal 
> needs a lot of care and testing. I would suggest to use smearing 
> and diagonalization. It will need much more CPU time but is safe. 
> regards 
> Juerg 
> -------------------------------------------------------------- 
> Juerg Hutter                         Phone : ++41 44 635 4491 
> Institut für Chemie C                FAX   : ++41 44 635 6838 
> Universität Zürich                   E-mail: hut... at chem.uzh.ch 
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> Winterthurerstrasse 190 
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> --------------------------------------------------------------- 
> -----cp... at googlegroups.com <javascript:> wrote: -----To: cp2k <
> cp... at googlegroups.com <javascript:>> 
> From: Aniruddha Dive 
> Sent by: cp... at googlegroups.com <javascript:> 
> Date: 03/22/2017 06:54PM 
> Subject: [CP2K:8838] Ab - initio MD of pure sodium 
> Hi, 
> I am performing ab - initio MD for pure sodium at 300K which is room 
> temperature. After 1 ps run, I find that the crystal structure of the pure 
> sodium does not remain purely crystalline. I am not sure as to why this is 
> happening. There shall be certain vibrations of the sodium ions but the rdf 
> plot becomes more of an amorphous type after 1 ps of MD run. The sodium 
> uses semi core basis sets which has 9 valence electrons and hence I need to 
> use a higher value of cutoff (~ 950 Ry) which is equivalent to 12925 eV. Is 
> this high value of cutoff correct? Or am I just using too high a cutoff and 
> as a result of which the sodium atoms are behaving as liquid sodium? 
> I have attached my input file and trajectory files hereby. 
> Kindly let me know what am I doing wrong. 
> Thanks and Regards, 
> Aniruddha M Dive 
> PhD Student 
> Washington State University 
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> [attachment "SODIUM_MD-pos-1.xyz" removed by Jürg Hutter/at/UZH] 
> [attachment "pure_sodium.inp" removed by Jürg Hutter/at/UZH] 
> [attachment "sodium.xyz" removed by Jürg Hutter/at/UZH] 
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