Problem with variable command:

Hi,
I’m a newcomer in this field. I have a system with two types of particles in it. Type 1 particles are within a spherical/spheroidal volume whereas there are only two type 2 particles outside the spherical/spheroidal volume. There are interactions between 1-1 and 1-2 type. The interactions contain a term which include the coordinates of both types of atoms. Can I use variable command in this framework?
I’m giving the term for your convenience.

Force between 1and 2=…exp (-(coordinate_of_type1 - coordinate_of_type2)/connstant)
how can I implement this force??

posting identical questions and multiple times per person and
from different people doesn't do anything to improve the question
or the chance to get a good answer.

i already answered to your colleague.

unless your are more clear about what kind model you
intend to implement (perhaps with a reference?) and
provide a more detailed description of what your potential
is like, nobody will help you.

since you state that you are new to the field, i highly
recommend to first spend some time understanding
how MD potentials are implemented in MD at all with
the ubiquitous example of a lennard-jones. there is a
load of details for that out there and the principles
remain the same. after you understood that, it will be
much easier for you to pose questions that can be
answered in a more satisfying way.

axel.