[gmx-users] g_dipoles

[Viswanadham Sridhara]

Hello Everyone,
Can anyone explain me how g_dipoles exactly work?
I am just briefly explaining what I did.
a) I took the whole trajectory and tried to find dipole moment,
-->full.xvg(This is with option -o)
b)then i divided the whole trajectory into two parts and tried to find the
dipole moment, first half-->fh.xvg and second half sh.xvg.
Obviously fh.xvg and sh.xvg combined is equal to full.xvg.

But, when i use option -a in g_dipoles, and tried to find <Mu>^2 - <Mu^2>
for the whole trajectory, the n umbers I found are different for the
trajectory when divided into two parts.

-------------------
g_dipoles -f full.gro -s dppc.tpr -o 1 -a 2 -mu 2.273 -mumax 5.0 -epsilonRF
78.5
g_dipoles -f firsthalf.gro -s dppc.tpr -o 11 -a 22 -mu 2.273 -mumax
5.0-epsilonRF
78.5
g_dipoles -f secondhalf.gro -s dppc.tpr -o 111 -a 222 -mu 2.273 -mumax
5.0-epsilonRF
78.5
-------------------------------------

In other words, concatenating 11 and 111 gives me 1.xvg, but not with 22 and
222......
How does Gromacs calculate <Mu>^2 and <Mu^2>......
Thanks in advance,
Viswam.



--
Viswanadham Sridhara,
Graduate Research Assistant,
Old Dominion University, "VIRGINIA".
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