AMBER Archive (2006)

Subject: RE: AMBER: RMS FLUCTUATIONS

From: Yong Duan (duan_at_ucdavis.edu)
Date: Thu Jun 15 2006 - 09:49:16 CDT

 
Jianwen,
 
If the concern is about T fluctuation, experimental T also fluctuates,
albeit very small with good T-control (mT-level). However, in the typical
scanning calorimetry experiments, (real) T can fluctuates considerably. The
T-fluctuation introduces uncertainty. Otherwise, I think the formula is
valid.
 
yong

-----Original Message-----
From: owner-amber_at_scripps.edu [mailto:owner-amber_at_scripps.edu] On Behalf Of
Jiang Jianwen
Sent: Thursday, June 15, 2006 4:37 AM
To: amber_at_scripps.edu
Subject: AMBER: RMS FLUCTUATIONS

Dear all,
 
I am not sure if "RMS FLUCTUATIONS of Energy (<U^2> - <U>^2)" from a NVT MD
simulation can be related to heat capacity Cv in the following way?
 
Cv = (<U^2> - <U>^2) / (kT^2)
 
Note that in a NVT ensemble with temperature coupling, T fluctuates.
 
Thank you for your comments.
 
Jianwen Jiang

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