[gmx-users] HF/6-31G** ESP derived charges to replace PRODRG assigned ones

[FyD]

Hi,

> Thanks for answering and sorry to take so long to reply. After your   
> response I went seach for more information about that. What I read   
> here in the list is that some people uses antechamber to generate   
> am1-bcc charges (or RESP charges using Gaussian program) and convert  
>  the output files to a .top file (using the amb2gmx.pl script) that   
> can be used in gromacs, however, nobody says the kind of ff they   
> intend to use that charges with. Do these type of charges can also   
> be used with Gromos96 ff ( 43a1)? Thanks in advance!

You could also use R.E.D.-III.2 http://q4md-forcefieldtools.org/RED/  
to generate RESP and ESP charges directly embedded in force field  
libraries (Tripos mol2 file format). You can select various algorithm  
to compute the MEP (CHELPG, or Connolly surface) and various fitting  
approaches (RESP or ESP). R.E.D. Server which interfaces R.E.D.-IV is  
now available http://q4md-forcefieldtools.org/REDS/ as well.

- You could use R.E.D. to generate Tripos mol2 files.
- Then, create the corresponding prmtop file using LEaP.
- Finally, convert the prmtop file into a format recognized by Gromacs.

regards, Francois