[gmx-users] Creating topology file for TBA cation using OPLS force field

[Andrey A. Koverga]

    Hi all! I'm just a beginner user of Gromacs, that's why my question may 
seem strange to you. But I hope, that somebody can help me in solving my 
problem. The point is that I'm trying to perform the analysis of 
tetrabutylammonium cation solvatation using OPLS force field. Earlier i've 
modelled tetrametylammonium cation with same force field; the topology *.itp 
file for TMA was created, using The Dundee PRODRG Server: itp-file was 
created for some Gromacs force field, and than modified by definition of the 
UA-groups according to OPLS UA-types. This way is unsuitable for 
determination of TBA topology, 'couse in this case "all-atom" determination 
should be performed. So that's why I'm asking your advise what should I do. 
Thanks a lot!