Using version 22Feb13.

I am working on thermodynamic integration of a system where some of

the particles in my system are changing from type 1 to type 2 which

uses a different set of LJ parameters: (epsilon and sigma). The

thermodynamic integration progresses across a series of simulations

according to a third parameter (lambda). When I introduce this lambda

parameter into my LJ potentials, my sigma12 and sigma6 become unique

functions of lambda.

Therefore, my question is this. In LAMMPS, is there a way to model an

LJ potential with three parameters: (epsilon, sigma12 and sigma6)? I

have looked and haven't had any luck short of coding it in myself, and

I thought I would ask here first before going with that option.

Thank you,