Local density CV for bubble nucleation

[Евгений Розанов]

Dear PLUMED users,

I am currently investigating argon bubble nucleation and have chosen to use PLUMED metadynamics for my study. However, I am encountering difficulties in selecting an appropriate collective variable (CV) for the transition.

I thought a natural idea would be to use local density in different regions of the simulation box. Unfortunately, it appears that PLUMED only allows for the calculation of density around a particular atom. The closest alternative I have considered is calculating the coordination number around ghost atoms placed on a lattice and clustering them; however, I have not been successful in obtaining appropriate results with cluster as a CV.

I would be very grateful for any advice, suggestions, or alternative approaches to implementing PLUMED for this problem.

Thank you,

E. O. Rozanov