Issue with High Bond and Angle Energies Leading to NaN Coordinates When Using CHARMM22 Force Field

[AuroraHuangyj]

Hi
When I use the CHARMM22 force field from the ff/charmm22 directory for equilibration, the bond energy and angle energy are always very high, which eventually causes the coordinates to become NaN. I tested with the examples provided in QligFEP, but the same situation occurred. It seems that the same problem arises with any protein when using CHARMM22. The attached files are related to the MD.

Q_charmm22_NaNProblem.tar.gz