Simulation H2 molecule by adding an additional site and massless

LAMMPS LAMMPS General Discussion
1

I want to simulate the H2 molecule using the model described in Phys. Rev. A 45, 8968 (1992) - Path-integral Monte Carlo techniques for rotational motion in two dimensions: Quenched, annealed, and no-spin quantum-statistical averages. In this model, the H2 molecule is represented as a two-site model by introducing an additional massless site (with charge) positioned between the two H atoms. I would like to know how to define the massless site in LAMMPS.

Thank you very much.

2

This is a common issue that has appeared several times in the forum, see for instance this post.