thermostat -thermostat control variable

DESCRIPTION

The thermostat variable is used to activate a thermostat that keeps the ionic temperature to a required value (th_temp).

If thermostat is set to ON, the ionic dynamics is modified by adding a friction (or acceleration) term (eta) to the equations of motion of the ions. eta is proportional to the difference between the instantaneous temperature (t) of the ions and the required temperature (th_temp). The friction/acceleration term is scaled in such a way that the thermostat reaches the required temperature on a time scale of the order of th_time.
 

eta = tanh( (t - th_temp) / 100 ) / th_time

R(t+dt) = R(t) + (1-dt*eta) * (R(t) - R(t-dt)) + F * dt² / m

Disclaimer: This is not a Nose thermostat, and should not be used as a way to simulate the canonical ensemble. It is a convenient device to reach a given temperature during a simulation. Statistical averages should be collected in microcanonical mode, after setting thermostat to OFF.
 

DEFAULT VALUE

OFF

ALLOWED VALUES

ON, OFF

RELATED INFORMATION

th_temp, th_time, atoms_dyn