[lammps-users] questions about energy conversation in RNEMD

From: Frank Yong <[email protected]>
To: [email protected]
Date: Wed, 22 Sep 2010 12:18:18 -0400
Subject: [lammps-users] questions about energy conversation in RNEMD

Dear All,

I am trying to calculate the fluid shear viscosity by RNEMD method using

...

temperature is expect to be a constant with natural fluctuations. In my
simulation, I simulate 6x106 time steps with time step as 0.005\tau.
The swap options are defaults, as swap=1 and vtarget=INF. The results
show a continuous decreasing of the total energy and temperature. Does
anyone have any idea why the energy is not conserved?

Using just the lammps 'melt' example, I've observed that energy isn't
conserved for the default LJ timestep of 0.005. The effect is small
but noticable. I'd expect this to be worse in RNEMD, particularly with
such an extreme swap rate.
-craig