Subject: I have yet ANOTHER stupid CHARMM question...

From: [email-masked]
Date: Fri, 19 Jul 2002 21:12:21 -0400 (EDT)

Hi all

I have yet ANOTHER stupid CHARMM question.

I'm doing a verlet simulation on a system other than a water box, namely 
my solvated peptide which I just fixed (finally).  I'm currently in the 
process of heating my system from 100 to 300 K in 50 K steps.

My question is this: what values should I use for IHTFRQ, the heating 
frequency, and TEMINC, the heating increment in degrees K?  My 50 K 
heatings run last for 10,000 time teps; I've broken it up into 4 10 ps 
heatings.

I was thinking something along these lines, namely that the number of 
steps divided by IHTFRQ times TEMINC should be equal to the change in 
temperature, or in this case 50.  In the CHARMm dictionary, 
published by MSI, there is an example where the number of steps, 
STEPS is 3000, IHTFRQ is 50, and TEMINC is 5.  Does this always 
hold, or am I goofy?  In my run, I've set IHTFRQ to be 100 and this 
means that TEMINC would be 0.5.  My NSTEPS are 10000.  Are these 
values of IHTFRQ and TEMINC ok?

Thanks in advance for your assistance.

Cheers,
Richard