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RASPA => General => Topic started by: Jacker on February 16, 2025, 03:51:12 PM

Title: No general mixing rule but I set is L-B
Post by: Jacker on February 16, 2025, 03:51:12 PM
Hi Dr Dubbeldam:

I am a new user to the RASPA2.0.
I have run the examples from the RASPA2.0 manual and my own tests, warning of atom-pairs with no VDW interactions have been found in the output files.

I am using RASPA2 to simulate the adsorption of CH4 on Aragonite (CaCO3) using UFF-Dreiding force field and methane molecule, and the results keep showing THERE ARE ATOM-PAIRS WITH NO VDW INTERACTION C-O C-Ca C-CH4_sp3 Ca-C Ca-O Ca-CH4_sp3 CH4_sp3-C CH4_sp3-O CH4_sp3-C CH4_sp3-O CH4_sp3-C CH4_sp3-O CH4_sp3-C CH4_sp3-C (maximum interactions shown).sp3 O-C O-Ca O-CH4_sp3 Ca-C Ca-O Ca-CH4_sp3 CH4_sp3-C CH4_sp3-O CH4_sp3-Ca (maximum 50 interactions shown); I set to general mixing rule for Lennard-Jones: Lorentz-Berthelot, but the result is "No general mixing rule: all cross term specified individualy",I have not found the reason for this, how to remove this warning, please advise me, thank you!

Best

Jacker
Title: Re: No general mixing rule but I set is L-B
Post by: David Dubbeldam on February 26, 2025, 03:47:11 PM
You have not specified the interactions for C-O C-Ca C-CH4_sp3 Ca-C Ca-O Ca-CH4_sp3 CH4_sp3-C CH4_sp3-O CH4_sp3-C CH4_sp3-O CH4_sp3-C CH4_sp3-O CH4_sp3-C CH4_sp3-C etc. Generally you will need to define these in the 'force_field_mixing_rules.def' file, using a self-interaction and a mixing rule to get the cross-interactions.