[gmx-users] How do Charge Groups work?

[Gale, Ella]

Dear Gromacs Users,

I had a system where I have no charges in it, but I do have Lennard-Jones non-bonded interactions. I've noticed that I get different values for the Lennard-jones interaction energy differs depending how I split the system up into charge groups (as the charge group concept is kinda abitrary in a system with no charges), this can not be right surely? 

As I understood it the charge groups were used to help compile the neighbour lists, but what I want is all the atoms within my cut-off radius to be in my pair-list (for that atom). Is there an option to ignore the charge groups? I find I get bigger Lennard-Jones interactions if I put my whole system into a charge group that if I split it up, but I need to split it up for my larger systems. Is there a way to increase the maximum number of charge groups? And is this a good idea?

I'm quite confused I'm afraid.

Thank you all for your ongoing help!

Regards

Ella Gale



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