Giovanni, Thanks for your quick response! I'll try to reduce the dt and 'restart' for restart_mode.
Thank you. Huiqun ----- Original Message ----- From: "Giovanni La Penna" <[email protected]> To: "PWSCF Forum" <pw_forum at pwscf.org> Sent: Monday, February 28, 2011 5:31 PM Subject: Re: [Pw_forum] temperature rescaling for vc-md > > I would suggest to heat the system slowly. > restart='from_scratch' > means that previous velocities are not loaded. > So going from zero (for a hopefully relaxed system) to 300 K, > with a time-step of 1 fs (if a remember correctly), may imply > a huge time to converge at each time step. > Even CP would not work properly this way: it runs, but temperature > oscillations become huge and the fake electron > kinetic energy would quickly increase, providing > an uncontrolled dynamics. > Other codes may have hidden controls on temperature, > time-steps, etc.. > > Giovanni > > ============================================================ > Giovanni La Penna - National research council (Cnr) > Institute for chemistry of organo-metallic compounds (Iccom) > via Madonna del Piano 10, > I-50019 Sesto Fiorentino, Firenze, Italy > tel.: +39 055 522-5264, fax: +39 055 522-5203 > e-mail: glapenna at iccom.cnr.it - http://www.iccom.cnr.it/lapenna > skype: giovannilapenna > ============================================================ > > On Mon, 28 Feb 2011, Huiqun Zhou wrote: > >> ... >> but the SCF convergence is always failed to reach after 20 or so ion >> steps >> no matter >> how I change mixing_beta from 0.5 to 0.05. One thing I noticed is that >> the >> temperature >> controling may be not in effect as the temperature remains as high as 6 >> digits. I used >> ... -------------------------------------------------------------------------------- > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum >
