[gmx-users] g_energy questions

[Andy Chao]

Dear GROMACS Users:

I would like to use the command g_energy to calculate the total free energy
of an electrolyte.  I use the following command:

g_energy -f NPT.edr -s NPT.tpr -b 0 -e 1000 -o energy.xvg


GROMACS4.6.5 printed out the following:

Select the terms you want from the following list by selecting either (part
of) the name or the number or a combination.  Enter your selection with an
empty line or a zero.

1. Bond   2. angle   3. proper-Dih   4 LJ-14......


My question is
A. what is the definition of each selection?  Which selection should I
choose to calculate the potential energy, kinetic energy, and the total
energy?

B. How can I change the time axis to calculate the energy beyond 200psec?
 What parameter must be chagned in the g_energy command?

Thanks!

Andy