[gmx-users] NVE Temperature Drop ONLY When Applying Restraints

[Diez Fernandez, Amanda]

Dear Users,
I was observing significant temperature drops in my system when switching from NPT equilibration to NVE.
Within 1ns of the NVE run the temperature was so low the water was freezing.
Trying to understand what was causing it, I have observed that it only occurs when I apply position restraints to certain water molecules (which I need to do for my final simulation).
Without any restraints the temperature does not drop.
I was wondering why this was happening.
Excuses in advance is this has already been discussed or has been explained elsewhere.

Many thanks,
Amanda