[lammps-users] A doubt about the stress/atom and pressure

Hi,
In my simulation I use real units. Here force is Kcal/mol-Angstrom and pressure is in atmosphere. In the force calculation we call stress/atom calculation ( by calling ev_tally, isn´t correct?). Then you pass the argument fpair. What is the unit fpair there? where do you convert that stress/atom to pressure. (force to pressure in atmosphere).?
thanks in advance…

In compute_stress_atom.cpp there is a comment line:

  // convert to stress*volume units = -pressure*volume

which is where the unit conversion takes place.

Steve

Hi,
fpair is having the dimension of force ?( I mean force Kcal/mol-Angstrom).?

There is no fpair variable in the current version of compute_stress_atom.cpp.

Steve

fpair variable is the one of the argument of ev_tally in the force->pair->compute function. What is the dimension(unit) of it.?

fpair = force/distance - see pair_lj_cut.cpp for an example.

Steve