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openforcefield / amber-ff-porting

Scratch space for porting amber FFs into SMIRNOFF format
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NTerm LEU energy discrepancies #24

Open j-wags opened 3 years ago

j-wags commented 3 years ago

CD1 and CD2 are chemically equivalent should have same charge, but they actually have slightly different charges (-0.4104 and -0.1406). This seems like a problem with the original FF, since they could be set to -0.4105 to resolve this issue.

It is impossible to solve this using the OpenFF toolkit, because the carbons are chemically equivalent.

j-wags commented 3 years ago

Original reference: https://github.com/openforcefield/amber-ff-porting/issues/18#issuecomment-681675869