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<p class=MsoNormal>Hi all,<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I am trying to incorporate a position dependent dielectric
constant.<o:p></o:p></p>
<p class=MsoNormal>The dielectric constant will have two different values:<o:p></o:p></p>
<p class=MsoNormal>\epsilon = \epsilon_ 1 r < r_c<o:p></o:p></p>
<p class=MsoNormal>\epsilon = \epsilon_2 r > r_c.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I know a simple way of implementing this;<o:p></o:p></p>
<p class=MsoNormal>F_new = F_old (estimated using \epsilon_2) + 1/(4pi)
\sum_{r < r_c} q_iq_j (1/\epilon_1 - 1/epsilon_2) rij/rij^3.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I looked through the PME code once it looks intimidating. If
any one can help me with this that would be great. I want to know how to access
the variables I need: q_i, q_j, \epsilon_r. Also, I want to do a neighbor
search; how to do efficiently do that in Gromacs (I don’t want to write
more inefficient algorithm). <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Thanks, Nazish. <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
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