AMBER Archive (2006)

Subject: RE: AMBER: RMS FLUCTUATIONS

From: Jiang Jianwen (chejj_at_nus.edu.sg)
Date: Fri Jun 16 2006 - 02:01:10 CDT

Dear Drs. Duan and Case
 
Thank you for your insightful comments.
 
Jianwen
 
 
 

________________________________

From: owner-amber_at_scripps.edu [mailto:owner-amber_at_scripps.edu] On Behalf
Of Yong Duan
Sent: Thursday, June 15, 2006 10:49 PM
To: amber_at_scripps.edu
Subject: RE: AMBER: RMS FLUCTUATIONS

 
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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