# [gmx-users] Nose-Hoover coupling constant

qiao rui ruiqiao at glsn12.ews.uiuc.edu
Tue Oct 21 18:45:01 CEST 2003

Hi,

I am thinking of applying the Nose-Hoover thermostat to my
simulation system. According to the manual, one should set the coupling
time constant to be 4-5 times larger than the "relax-time"
used in the weak-coupling. If I am using a 0.1ps as coupling constant for
weak-coupling, then does it means I should use 0.5ps for the N-H
thermostat? What time constant is commonly used?

The manual says that the usually used coupling constant Q in
the N-H thermostat is related to the coupling constant (t_tau) by
Q = t_{tau}^2 T_0 / 4 \pi^2
Is this a rigious relationship? Where can I find a reference for
that? (The reason I ask is that I feel that in presenting the simulation
details to people who may not be familiar with Gromacs, using Q may be
easier to understand).

Thanks a lot!

sincerely,

Rui
------------------------
Rui Qiao
Research Assistant
Beckman Institute, UIUC