[gmx-users] Rotational correlation function for water
pravink068 at gmail.com
Tue Aug 9 09:33:37 CEST 2016
I am calculating the rotational correlation time for water (SPC/E model) by
using the following command-
g_rotacf_mpi -f traj.trr -s pr.tpr -n ind.ndx -P 1 -o watr_ohh.xvg -fitfn
I am getting the correlation time
COR: Correlation time (plain integral from 0.000 to 2505.000 ps) =
I have define a group containing three atoms (OW HW1 HW2) in index file .
If, i take two atoms (OW and HW1, suppose if i want to calculate rotational
correlation time along O-H vector), then i am getting correlation time
COR: Correlation time (plain integral from 0.000 to 2505.000 ps) = *4.80207
by using command-
g_rotacf_mpi -f traj.trr -s pr.tpr -n ind.ndx -P 1 -d -o watr.xvg -fitfn
It is reported 1.71 ps (by NMR experiment) and 2.0 ps< (by MD simulation
for SPC/E model).
Could anybody help me to understand, where am i doing wrong?
All these calculation are done from 5 ns production run (NVT ensemble) at
INDIAN INSTITUTE OF SCIENCE
EDUCATION AND RESEARCH PUNE
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