[CPMD-list] experienced problem

[liuzhim]

Dear Dr. apsi:
       Thanks for your eaplainations. I am still using CPMD Version 3.9, because I have lost my download password to CPMD.org and missed the chances to upgrade the powerful package. I don't know what or/and how to do with the mistake I have made.
      By the way, I am interested in what we need every day-- the phase of water/ice. Say: The best way to look into a package is to run the examples. The cpmd_test provides a cubic WAT32 example for STANDARD MD simulations. 
     During the trial, I found the PP for H and O are using inconsistent correlation functionals. and the kinetic energy for electrons, Ekin converges to about 0.02.
    My work starts from water /ice phase X with 16 molecules and lattice parameter varies from 5.4 angstrom to 6.2 angstrom to phase VII, at 300K(ambient temperature). When a0 >= 5.7  and =< 6.1, the Ekin oscillates around 1.0 a. u., exhibits convergency. Otherwise it increases to 0.01~0.02 with no oscillate curvatures observed(although it seems to be converged).
     I wonder if what above mentioned is physically reasonable. Additionally, I have tried to re-optimize wavefunctions every 500 MD steps. Surprisingly, at the second round of 500-Step MD, it increases to ~1.0 and oscillates, but delines to ~0.02 in the next round.
    I am looking forward to your advices. the main part of my CPMD script is as what follows.
                                Thanks a lot
                                       Z. M. Liu
                                        liuzhim at mail.jl.cn
                                           Dec. 17, 2007    
&CPMD
      OPTIMIZE WAVEFUNCTION/MOLECULAR DYNAMICS cp
      TIMESTEP
      4
      MAXSTEP
      500
     EMASS
     1100.0
     TEMPCONTROL IONS
     300.0 70.0
     TRAJECTORY XYZ
     TEMPERATURE ELECTRONS
     1000.0
     &END
    
            

----- Original Message ----- 
From: "Ari P Seitsonen" <ari.p.seitsonen at iki.fi>
To: "liuzhim" <liuzhim at mail.jl.cn>
Cc: <cpmd-list at cpmd.org>
Sent: Sunday, December 16, 2007 10:17 PM
Subject: Re: [CPMD-list] HELP: Explaination to manual 9.5.2


> 
> 
> Dear Mme/Mlle/M Liu,
> 
>   That sentence ONLY applies to calculations in the electronically excited 
> state (employing TDDFT, that chapter is meant to be read only when using 
> TDDFT). However, it is always preferable to perform an optimisation of the 
> wave functions before a molecular dynamics run when running the 
> Car-Parrinello MD, it is a common source of error to try start directly 
> with the dynamics.
> 
>     Greetings from Strasbourg,
> 
>        apsi
> 
> PS Which version of the code are you using?
> 
> On Sun, 16 Dec 2007, liuzhim wrote:
> 
>> Hi, every body:
>>   I have a question to the manual for CPMD, and hope somebody may give help.
>>    I want to handle some finete temperature simulations via CPMD.  All 
>> the examles were tried. Recently, when I read the manual carefully, the 
>> sentence  "geometry optimizations and molecular dynamics simulations can 
>> only be performed after an electronic spectra calculation" in section 
>> 9.5.2 makes me much confused. Does it mean that I should calculate the 
>> electronic spectra even though I just want to perform a dynamical 
>> simulation  to investigate the mechanical or thermal properties for ions 
>> while the electronic properties are neglected? If I do not do the 
>> spectra work, what will occur to the results?
>>                                                        Z. M. Liu from , Changchun, P.R.C
>>                                                         Dec. 16, 2007
>>                                                        liuzhim at mail.jl.cn
>>                                                                 .
>> _______________________________________________
>> CPMD-list mailing list
>> CPMD-list at cpmd.org
>> http://cpmd.org/mailman/listinfo/cpmd-list
>>
> 
> -- 
> -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
>   Ari P Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
>   IMPMC, CNRS & Université Pierre et Marie Curie
>   Tel: +33-1-4427 7542, Fax: +33-1-4427 3785, GSM: +33-6-6736 3820