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<p style="margin-top:0;margin-bottom:0"><span style="font-size: 11pt;">Dear GROMACS developers,</span><br>
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<div><span style="font-size:11pt">Would it be possible to utilise an additive potential alongside that calculated in GROMACS from standard force-fields? Specifically, we are looking at using a machine-learned potential (GAP) to introduce the effect of a metal
ion centre into an MM (water) system. We’d like to train the potential on the</span><span style="font-size:11pt"><span style="font-size:11pt"> difference between
</span><span style="font-size:11pt">an QM/MM calculations with and without Pd</span></span><span style="font-size:11pt"><span style="font-size:11pt">, then sum the difference in force experienced by the surrounding atoms to the MM force calculated using the
normal MM strategy (and likewise with the energy). </span><span><span style="font-size:11pt">In practice: include a standard dummy
</span><span style="font-size:11pt">metal centre</span><span style="font-size:11pt"> and then leave it with 0 vdw/charges and introduce the potential on the top of the empirical one. it will replace the metal + add extra forces to the water close.</span></span></span></div>
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<div><span style="font-size:11pt"><span style="font-size:11pt">The potential is implemented within QUIP (https://github.com/libAtoms/QUIP), written largely in fortran95. It requires the number of atoms (int), atomic numbers (int, Nx1 array), positions (dp,
Nx3 array). We would like to have</span><span><span style="font-size:11pt"> this as an external source of forces on the central atom and
</span><span style="font-size:11pt">wonder if</span><span style="font-size:11pt">
</span><span style="font-size:11pt">the IForceProvider interface would provide a way to do so</span><span style="font-size:11pt">.
</span><span style="font-size:11pt">If so, is </span><span style="font-size:11pt">this</span><span style="font-size:11pt"> possible in the current implementation? </span></span></span></div>
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<p style="margin-top:0; margin-bottom:0"><span style="font-size:11pt">Many thanks in advance for your help.</span></p>
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<span style="font-size:11pt"></span><span style="font-size:11pt"></span><span style="font-size:11pt"></span><span style="font-size:11pt; font-family:Calibri,Helvetica,sans-serif"><span style="font-family:Calibri,Helvetica,sans-serif; font-size:11pt">Best wishes,</span></span></p>
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<span style="font-size:11pt"></span><span style="font-size:11pt"></span><span style="font-size:11pt"></span><span style="font-size:11pt; font-family:Calibri,Helvetica,sans-serif"><span style="font-family:Calibri,Helvetica,sans-serif; font-size:11pt">Fernanda</span></span></p>
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<span style="font-size:11pt; font-family:Calibri,Helvetica,sans-serif"><span style="font-family:Calibri,Helvetica,sans-serif; font-size:11pt">Dr </span><span style="font-family:Calibri,Helvetica,sans-serif; font-size:11pt">Fernanda Duarte </span></span></p>
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<span style="font-size:11pt"></span><span style="font-family:Calibri,Helvetica,sans-serif; font-size:11pt">Associate </span><span style="font-family:Calibri,Helvetica,sans-serif; font-size:11pt">Professor of Chemistry</span><br>
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