| version 1.9 | version 1.10 |
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| \NAMDCONFWDEF {fepElecLambdaStart}{\FEP\ lambda start-point for electrostatics} | \NAMDCONFWDEF {fepElecLambdaStart}{\FEP\ lambda start-point for electrostatics} |
| {positive decimal} | {positive decimal} |
| {0.} | {0.5} |
| {In order to avoid the FEP ``end-point catastrophe", it is often important to make sure that a growing particle does not have an unbounded potential right at the moment that it is created (in case that it appears on top of another particle). One way to deal with this for electrostatic interactions, is to allow a bounded scaled vdW potential (using a positive {\tt fepVdWShiftCoeff}) to first repel all overlapping particles at low values of $\lambda$. As $\lambda$ increases, once the particles are repelled, it is now safe to turn on FEP electrostatics. {\tt fepElecLambdaStart} is the value of the scaling factor $\lambda$ at which electrostatic interactions are turned on and start ramping up linearly; below this value, electrostatics are turned off for all FEP particles. Note: what is really being modified is the $\lambda$ factor that directly multiplies the interactions (\emph{i.e.}, 0 = fully off, 1 = fully on), rather than the $\lambda$ provided by the user, which may sometimes correspond to (1 - $\lambda$).} | {In order to avoid the FEP ``end-point catastrophe", it is often important to make sure that a growing particle does not have an unbounded potential right at the moment that it is created (in case that it appears on top of another particle). One way to deal with this for electrostatic interactions, is to allow a bounded scaled vdW potential (using a positive {\tt fepVdWShiftCoeff}) to first repel all overlapping particles at low values of $\lambda$. As $\lambda$ increases, once the particles are repelled, it is now safe to turn on FEP electrostatics. {\tt fepElecLambdaStart} is the value of the scaling factor $\lambda$ at which electrostatic interactions are turned on and start ramping up linearly; below this value, electrostatics are turned off for all FEP particles. Note: what is really being modified is the $\lambda$ factor that directly multiplies the interactions (\emph{i.e.}, 0 = fully off, 1 = fully on), rather than the $\lambda$ provided by the user, which may sometimes correspond to (1 - $\lambda$).} |
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| \NAMDCONFWDEF {fepVdwLambdaEnd}{\FEP\ lambda end-point for van der Waals} | \NAMDCONFWDEF {fepVdwLambdaEnd}{\FEP\ lambda end-point for van der Waals} |
| {positive decimal} | {positive decimal} |
| {1.} | {0.5} |
| {If one is using the {\tt fepElecLambdaStart} option above, one may wish to further decouple the scaling of van der Waals and electrostatic interactions. {\tt fepVdwLambdaEnd} sets the value of $\lambda$ above which all vdW interactions will be fully on. Note: what is really being modified is the $\lambda$ factor that directly multiplies the interactions (\emph{i.e.}, 0 = fully off, 1 = fully on), rather than the $\lambda$ provided by the user, which may sometimes correspond to (1 - $\lambda$).} | {If one is using the {\tt fepElecLambdaStart} option above, one may wish to further decouple the scaling of van der Waals and electrostatic interactions. {\tt fepVdwLambdaEnd} sets the value of $\lambda$ above which all vdW interactions will be fully on. Note: what is really being modified is the $\lambda$ factor that directly multiplies the interactions (\emph{i.e.}, 0 = fully off, 1 = fully on), rather than the $\lambda$ provided by the user, which may sometimes correspond to (1 - $\lambda$).} |
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