Morning every one,
First of all, I want to say Muller Plathe method is a good method. however, I find it only to be applied to atoms of same types, so I tried to modify it to be applied to atoms of different types days ago.
I only made the Muller Plathe to satisfy the momentum and energy conservation with different mass, and I got the formula which can be used to different types, and I find it work well.
So here I want to enjoy it with every one, of cource ,maybe it’s wrong, so would you please check it for me? thanks
the formula i got is as follows:
I suppose the mass of the hot atom is m1, whose velocity is v1; and for the cold one is m2 and v2. After velocity interchange, i change the v1 to be v1 + 2beta/(beta+1)(v2  v1) and v2 to be (2*v1 + (beta  1)*v2 ) / (beta+1)

Matt  do you want to check with this person and see
if what he wants to do makes sense and is correct for fix viscosity?
Steve