Dear All,

I would like to calculate the thermal conductivity of a simple one component LJ system using LAMMPS. The Green-Kubo relation to calculate thermal conductivity (lambda) is:

lambda = ( 1/(3*V*kB*T^2) ) * Integral( 0 to infinity){ <**j**(0)**j**(t)>} dt

where

**j**(t) = sum (over i) {**v** ei} + 0.5* Sum (over i,j; i not eq j) { (**F**ij dot **v**i) **r**ij }

However, I have not been able to locate the variable, (if it exists) that gives the force between a given pair of particles. This would be required to perform the above calculation.

Please can you point me as to whether such a variable exists / any other way I can get a handle to this quantity.

If not, could you please provide access to this variable in the next release of LAMMPS? Similarly, a variable that gives the potential between two specified particles would also be helpful.

Any suggestions in performing the above calculations are welcome.

Cheers!

Mario Pinto

PS: I have looked at the thermal/conductivity fix, but that works only for particles of the same mass; However in the near future I would like to carry out computations for systems consisting of a mixture of particles.