calculation of the pressure tensor

Dear all,

As I understand the manual, the various components of the pressure tensor include contributions from the intramolecular forces, that is dihedral, angle and bond forces. Therefore, I wonder whether it is possible to calculate the pressure tensor without these contributions, so that the pressure tensor components only include the pair forces and long range forces and the kinetic contributions? Moreover, is it possible to calculate a molecular pressure tensor rather than an atomic pressure tensor, including the kinetic contributions, pair forces and long range forces?

Thank you in advance for an answer

Sten Sarman

You should be able to use the ke, pair, bond, etc. keywords of compute pressure (http://lammps.sandia.gov/doc/compute_pressure.html). Likewise for compute stress/atom if you want the per-atom stress tensor.

As for the second point, as far as I know it's not possible to sum properties over molecules like this at the moment. You'd have to do it as a postprocessing job.