[gmx-users] non isotropic kinetic energy

[aherz]

Hi,

we're running simulations of a water slab sandwiched by vacuum (ca. 2k
waters, 3x3x12 nm^3 box) in NVT
and look at the pressure tensor. We are surprised to find that the
kinetic energy is equivalent (within statistical uncertainty) for x and
y dim(parallel to the interface) but not in z dim. This appears to
violate the equipartition theorem?

This is gromacs 3.0 and 4.0 using berendsen thermostat.

Alex