Previous Thread
Next Thread
Print Thread
Joined: Sep 2008
Posts: 4
R
rssc Offline OP
Forum Member
OP Offline
Forum Member
R
Joined: Sep 2008
Posts: 4
Dear charmm users,

I am trying to run a CPT dynamics in a given molecular crystal. However, I am not sure if I should the same value of "pgamma" value during the entire molecular dynamics run (i.e., heating, equilibration, and production).

Currently, I am using the following for the HEATING step:
pcons pint pref 1.0 pmass 2000 pgamma 25.0 -

And the following for the EQUILIBRATION step:
pcons pint pref 1.0 pmass 2000 pgamma 5.0 -

Any directions on how to define the pmass and/or pgamma values will be appreciated.

Thanks,

Joined: Sep 2003
Posts: 8,623
Likes: 24
rmv Online Content
Forum Member
Online Content
Forum Member
Joined: Sep 2003
Posts: 8,623
Likes: 24
There is some debate about the best practice for that. Setting PGAMMA to zero does give true NPT or NVT dynamics. OTOH, a non-zero PGAMMA is equivalent to a chain of thermostats for T control. Finally, some claim that all thermostats and barostats are flawed, and only NVE dynamics should be used.

1 member likes this: shane yue

Moderated by  BRBrooks, lennart, rmv 

Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5
(Release build 20201027)
Responsive Width:

PHP: 7.3.31-1~deb10u1 Page Time: 0.008s Queries: 19 (0.005s) Memory: 0.7290 MB (Peak: 0.7689 MB) Data Comp: Off Server Time: 2022-12-04 21:01:09 UTC
Valid HTML 5 and Valid CSS