Dear MS Community,

I recently ran a 200 ns NVT dynamics simulation (using the Forcite module), which generated a cell.txt file reporting the Final Total Energy as -26285.366 kcal/mol.

To better understand this, I carried out two additional tasks:

1. .xtd file: I ran the Energy task (Forcite module) on the .xtd file generated after the same 200 ns NVT run. The cell.txt file reported the total energy for all frames in this trajectory, with values ranging between -35000 and -36500 kcal/mol. Notably, the total energy of the last frame was -36130.988 kcal/mol.
2. .xsd file: I then ran the Energy task (Forcite module) on the .xsd file generated after the same 200 ns NVT run. In this case, the cell.txt file reported the total energy for a single frame (the last frame), which was again -36130.988 kcal/mol. This value matches exactly with the total energy of the last frame obtained from the .xtd file.

My question is: why is the energy reported directly after the NVT dynamics run (-26285.366 kcal/mol) not in agreement with the energies obtained by running the Energy task on the .xtd and .xsd files (-36130.988 kcal/mol)?