[gmx-users] energy units

[Ashish Gupta]

Hello gmx-users:

   I posted a question on the group sometime back but I think I made my 
question too complicated to answer. So let me put it in a simpler way

The energy units are   (mass* length* length)/(time*time) . So for gromacs 
it is   (amu *nm*nm )/(ps*ps) . Hence when gromacs reports total energy in 
units of KJ/mol all I have to do to convert it to KJ is divide it by 
Avogadro number. Please correct me if I am incorrect.

But then why does g_energy have -nmol (default value = 1) option with it. 
Why do we have to specify the total number of molecules here since we can 
always find the total energy of the sytem by dividing the energy reported in 
KJ/mol by Avogadro number to get the total energy of the system in KJ.

I am relatively new to gromacs and highly appreciate any help,
Best Wishes,
Ashish.