Coadsorption in framework

add_to_config will allow you to cram way more molecules into a system than are thermodynamically reasonable. I tried using it to add 50 TCP molecules to the faujasite framework, and it slotted three TCP molecules into a single zeolite cage. As you can imagine, that's a high energy configuration, but due to the pore structure of faujasite even a short NVT ensemble couldn't shake those 3 molecules apart. Sure enough, when I started a GCMC sim, it crashed when attempting to delete one of those 3 TCP molecules. The problem lies in trying to compute the reverse probability for inserting that molecule back into the location it's being deleted from. If the reverse move is more than 708kT uphill, then the acceptance probability of the move blows up.

If you really want a faujasite crystal loaded with TCP to start your sim, I think you'd be better off running a short GCMC simulation without water and with a high chemical potential for TCP. The beta*mu*N term will facilitate high loading, but the beta*deltaU term will prevent high energy configs from being accepted.

I also recommend that you run in equilibration mode so your maximum translation and rotation deltas can be adjusted. The values in your input file (5 Angstroms, 90 degrees) give relatively low acceptance (1%) of your translation and rotation moves for TCP. Also, computing the pressure in a simulation box with a rigid zeolite framework is physically meaningless and computationally expensive.