[Pw_forum] vc-md temperature increases

[Lily Anh]

Hi Paolo,

Thanks for the reply. I added the following lines in the &ions section:

    ntcheck=100,       !  temperature is checked every ntcheck timesteps
    ntimes=10          !  maximum number of velocity rescaling

and the calculation crashes "    from  read_namelists  : error #        88
      reading namelist ions"

How to fix this?

Lily

________________________________
 From: Paolo Giannozzi <giannozz at democritos.it>
To: Lily Anh <lily_physics at yahoo.com.sg>; PWSCF Forum <pw_forum at pwscf.org> 
Sent: Monday, 5 December 2011, 23:10
Subject: Re: [Pw_forum] vc-md temperature increases
 
On Mon, 2011-12-05 at 17:13 +0800, Lily Anh wrote:
> 
> I am running a 'vc-md' calculation with PW.X in QE v4.1.1. The system
> is bcc-Fe supercell of 16 atoms. The target temperature were set to
> 600 K in the input file while the temperature goes up all the way to
> more than 1000 K.

velocity rescaling is present in the variable-cell MD algorithm but 
it is not actually activated. You will need to initialize variables
"ntimes" and "ntcheck", used by subroutine "vcmove" in PW/vcsubs.f90,
to the number of thermalization steps to be performed and to the 
number of steps between thermalizations; or to use the development
version (just fixed, maybe)

P.
-- 
Paolo Giannozzi, IOM-Democritos and University of Udine, Italy
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