 # [lammps-users] units in DPD fluid

Hi all users,
I want to ask something on how to change units Lj in real units.
I ran a DPD simulation with
KbT=1,0 ,
mass= 1,0 and
rc=1,0.
My channel is equal to 10sigma.
I want to ask this think. I got confused on that:
when i use mass=1,0 it means that i have a fluid of one atomic unit mass=1,66X10(-27)Kg?? Cause if i can determine the type of clusters i use then i can estimate the distance in Angstrom, the energy unit, the temperature ( i mean when i say kBT=1 what this mean in kelvin units) e.t.c.
For example if the atom type is Ar the 1sigma distance=3,405A.
Am i right?? Could anyone help me on this?? Thank u very much in advance.Jim

In LJ units, mass is not atomic mass units, but unitless
LJ mass. If you want to run the equivalent system
in real units for Argon, you would use the sigma, epsilon
for Argon (you can look it up), and the mass of Ar in
amu, and a T in degrees K (relative to the epsilon for Ar).

Steve

2008/4/11 ΔΗΜΗΤΡΙΟΣ ΛΑΔΑΣ <[email protected]>:

Dear Lammps users,
What if i want to give the unitless mass, temperature e.t.c i used in my simulation (in LJ units) in real units? Is there any way to express whatever i used and whatever i estimated in my simulation already in real units without giving real units in advance?? Thank u very much for your time. Jim

Steve Plimpton [email protected] ������:

Yes, you can run in LJ units, then convert your output
to real units at various state points. See a textbook
that discusses LJ (reduced) units.

Steve

2008/4/11 ΔΗΜΗΤΡΙΟΣ ΛΑΔΑΣ <[email protected]>: