Problem with charged system

Javad,

Good to know that you were able to run Cassandra on a different machine.

If the double ring is rigid then you can still run a simulation in Cassandra by treating the fused ring as one fragment.

Osmotic ensemble is currently not supported in the current version of the code. But as you rightly pointed out that one can perform an NPT Gibbs ensemble simulation. If the fugacity vs pressure dependence is known, it can be used to set the pressure.

Jindal