[gmx-users] atom types / FF

[Arturas]

Hallo,

Some my previous simulations are done with ffG43a1. Now, I'm
simulating drug-protein complex. Drug has 'CR61' atom type that is not
implemented in ffG43a1, but in gmx  - is. 

Is any way to add 'CR61' atom type to 43a1 including somethere
gmx*.atp file or any similar way?

And more general question on FF: how implemented FF in GROMACS are
comparabale with each other ? Let's say the mentioned 43a1 vs. gmx ?

With best
Arturas