[CP2K-user] [CP2K:10848] Equation of State calculations for Na2S Crystal

[Aniruddha Dive]

Hi Juerg,

Yeah I am using the same k-point settings in all calculations. With GAPW I 
am getting a much closer match with VASP optimized lattice parameters but I 
am getting the charge density on grid to decrease with each step during 
optimization reaching a final value of 0.0000005694 whereas with GPW I do 
get a very low value of charge density on grid but the lattice parameters 
are slightly lower than those obtained through VASP. Do I need to use GAPW 
of the GPW method to calculate the equation of state energies? Also for the 
GAPW method do I need to increase the cutoff so as to decrease the value of 
charge density on grid?

Thanks,
Aniruddha M Dive

On Tuesday, October 16, 2018 at 12:23:04 AM UTC-7, jgh wrote:
>
> Hi 
>
> are you using the same k-point settings in all calculations? 
>
> regards 
>
> Juerg Hutter 
> -------------------------------------------------------------- 
> 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 
> <javascript:> 
> Winterthurerstrasse 190 
> CH-8057 Zürich, Switzerland 
> --------------------------------------------------------------- 
>
> -----cp... at googlegroups.com <javascript:> wrote: ----- 
> To: "cp2k" <cp... at googlegroups.com <javascript:>> 
> From: "Aniruddha Dive" 
> Sent by: cp... at googlegroups.com <javascript:> 
> Date: 10/16/2018 01:24AM 
> Subject: [CP2K:10848] Equation of State calculations for Na2S Crystal 
>
> Hi All, 
>
> I am trying to calculate the Equation of State curve for Na2S unit cell 
> using CP2K. 
>
> To start off the calculations, I am performing a cell optimization of a 
> single unit cell of Na2S. Please find attached the input for cell 
> optimization. After optimization I obtain cell parameters to be a=b=c=4.575 
> as compared to (cell parameters from VASP of same unit cell a=b=c=4.646). 
> The lattice parameter values are fairly close to one another. However, the 
> fractional coordinates change significantly in the final optimized unit 
> cell from the starting configuration. 
>
> How do I resolve this issue? I am currently using GPW method with a very 
> high cut off of 1300 Ry to account for hard basis sets for Na. I have also 
> tried using GAPW method with a low cutoff of 550 Ry but with GAPW method I 
> obtain the charge density on grid value to be ~ 0.0000005694 as compared to 
> charge density on grid of 0.0000000003 for GPW methods. Also find attached 
> input file for GAPW method. With GAPW method I get the lattice parameters 
> to be a=b=c=4.642. I would like to know if I should proceed with GAPW 
> method or GPW methods to calculate the equation of state curves for Na2S? 
>
> Regards, 
> Aniruddha M Dive 
> PhD Candidate 
> Washington State University 
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> [attachment "cell_opt_GAPW.inp" removed by Jürg Hutter/at/UZH] 
> [attachment "cell_opt_GPW.inp" removed by Jürg Hutter/at/UZH] 
> [attachment "na2s_opt_GAPW.log" removed by Jürg Hutter/at/UZH] 
> [attachment "na2s_opt_GPW.log" removed by Jürg Hutter/at/UZH] 
>
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