Dear espressoMD mailing list,

I am trying to set up a NPT simulation for colloids that are interacti=
ng via Yukawa potential and WCA potential. The manual of version (3.3.1) st=
ates that:

the particle velocities (e.g. Langevin or DPD), and a thermostat for the bo= x geometry (e.g. the isotropic NPT thermostat)"

I have then implemented a script with those lines:

integrate set npt_isotropic

thermostat npt_isotropic *temperature gamma0 gammaV*

thermostat langevin *temperature gamma*

To understand how to set the friction factors and the piston mass I am=
referring to the paper J.Chem. Phys., 111(10):4453–59, 1999.

At this point it is not clear to me the meaning of the friction factor=
s in the command above.

According to the paper by Kolb and Dunweg there are two damping parame=
ters. The damping
γ0 in the paper is related to the particle relaxation time whil=
e
γV is related to the volume relaxation time. Are those two fact=
ors in the paper coinciding, respectively, with
*gamma0* and *gammaV* of the NPT isotropic protocol described=
by the command line above ?

My doubts comes from the fact that I have found a link where the value of t= he parameters

setmd piston 0.0001

setmd g0 0.001

setmd gv 0.5

But g0 assumes the optimal value of γV in the paper, while gv assumes the optimal value of γ0 in the paper.

Furthermore, I would like to understand better the role of the "Langev= in" command line. The temperature in "thermostat npt_isotropic&qu= ot; should be the same as in "thermostat langevin" command ? Gamm= a should not be equal to the the friction term for the particles velocities, then coinciding with gamma0 ?

setmd g0 0.001

setmd gv 0.5

But g0 assumes the optimal value of γV in the paper, while gv assumes the optimal value of γ0 in the paper.

Furthermore, I would like to understand better the role of the "Langev= in" command line. The temperature in "thermostat npt_isotropic&qu= ot; should be the same as in "thermostat langevin" command ? Gamm= a should not be equal to the the friction term for the particles velocities, then coinciding with gamma0 ?

Thank you in advance for your attention