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<DIV><FONT face=Arial size=2>Hi all,</FONT></DIV>
<DIV><FONT face=Arial size=2> I already posted this
question on the developer's list, but nobody answers it. So I posted it here
again. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2> In Gromacs,
"energygrp_excl" can exclude all non-bonded interactions between pairs of energy
groups. But I only want to </FONT></DIV>
<DIV><FONT face=Arial size=2>turn off the electrastatic interaction between 2
energy groups.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2> The following is my
idea. (I choose Cut-off for electrastatic calculation and use grid for the
neighbour searching.)</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2> There are 3 short
range neighbour-lists generated in ns.c(vdw, coup, vdwc). It seems to me
that "vdwc" will store the information of the </FONT></DIV>
<DIV><FONT face=Arial size=2>particls with both charges and the lj type. "vdw"
will store the information of the particles whose charge is 0, and
"coup" will store the information </FONT></DIV>
<DIV><FONT face=Arial size=2>of the particles whose lj is 0.(not
sure?) What I have done is to loop over the charge groups and judge if the
2 groups are excluded, if they are,</FONT></DIV>
<DIV><FONT face=Arial size=2>I just add the particles in that group into "vdw"
list instead of "vdwc" list. Then it seems to me that only vdw interaction is
computed even if the </FONT></DIV>
<DIV><FONT face=Arial size=2>charge are not 0 for those particles.</FONT></DIV>
<DIV><FONT face=Arial size=2> But when I tested it, it did not
work. Before I did the exclusion, the elecstatic intereaction of the system
is 0.16 kj/mol, but after I chose the </FONT></DIV>
<DIV><FONT face=Arial size=2>exclusion, the </FONT><FONT face=Arial
size=2>elecstatic intereaction of the system is -201 kj/mol. It seems that
the 1-2, 1-3 neigbours are even computed. (My system includes </FONT></DIV>
<DIV><FONT face=Arial size=2>1 spc water </FONT><FONT face=Arial
size=2>molecule and 1 pf6 molecule).</FONT></DIV>
<DIV><FONT face=Arial size=2> Do you know what is wrong
with my idea, and is there a better way to do this?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Thank you very much!</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Best</FONT></DIV>
<DIV><FONT face=Arial size=2>Xuhui</FONT></DIV>
<DIV><FONT face=Arial size=2> </FONT></DIV>
<DIV><FONT face=Arial><I><BR></I></FONT> </DIV>
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