[CPMD-list] Energy components in PIMD

[Łukasz Walewski]

Dnia 2008-05-18, nie o godzinie 16:49 -0400, Axel Kohlmeyer pisze:
> On Sun, 18 May 2008, ukasz Walewski wrote:
> 
> dear lukasz,

Dear Axel,

> LW> > you can rescale more often, say every 25th step? that would make
> LW> > the disruptions smaller (but more frequent).
> LW> 
> LW> This seems to me negatively verified - on the second attached graph the
> LW> black plot is the total energy with COM motion removal every 10'000
> LW> steps and the red plot - every 25 steps. The plots speak for themselves.
> 
> yep. so either you have to live with what you have using the 
> translation/rotation correction infrequently, remove the subtract
> COMVEL/ROTVEL altogether after equilibration or use 3 or 4 _very_
> soft position _restraints_ on some of the outer carbon atoms that
> will also make sure that the system stays where it should.

Well, I will try the last option. However I have no clue on what "very
soft" means, i.e. what might be the "soft" value for kval ? The manual
is silent on the units of this parameter. Otherwise one could have taken
the force constant of the C-H bond from any common force filed (e.g.
Gromos) and divide it by 10 or even 100. What is your recommendation ?

Best regards,
Lukasz