How does the frog module incorporate the virtual cavity in its calculations?

[Wilberth Narvaez]

Hello,

Where can I find information regarding the "virtual cavity" option available in the mdprep menu?
I have already read the manual, but the information available is scarce. Specifically, I would like to comprehend how velocities are re-scaled upon impact against the barrier.

Best,
Narvaez

[Arnim]

Hi Narvaez,

the velocity change by the barrier is calculated via Hooke's law and is scaled by the ratio of the temperature of the barrier and the instantaneous temperature of the atom.
Like this:
v = v + tratio * dv
with
tratio  = barrier temperature / instantaneous temperature
dv = dt * F_barrier / m
with F_barrier = - spring constant * dx

Hope that makes it clearer,

Arnim