AW: AW: Generating force field for novel molecules

From: Norman Geist (
Date: Fri May 25 2012 - 00:56:07 CDT



if I remember correctly, there was a post to this list about the release of a tool called paratool, with it, it should be possible to generate force field parameters for charmm and I’m sure there are a lot of tutorials for it.


If you read through some papers you will see that generating all ff parameters by yourself can however be a project itself and too time consuming. Often people only compute the partial charges of their molecules with this QM and use the other parameters from publications and similar molecules. If your molecule doesn’t contain anything special, that would be the best thing I guess. If it is really special, you should search for published parameters. Also, if you try to generate all parameters from the ground up, you will have to verify them in many tests. The bottom line is, generating a full set of parameters is too much work, especially for torsion angles if you have sugars or similar.


The standard procedure for amber partial charges and ff type guessing is pretty easy.

1. Gaussian/Gamess energy optimization

2. Gaussian/Gamess electro static potential

3. Antechamber

4. Some after work if force field typing mistakes


For charm, I would inform about that paratool.


Please remember that you always should know what you are doing. I will not help you to only follow tutorials to generate parameters that you don’t understand. Quantum mechanics is the base of force field, so it won’t harm to know it a little.


Norman Geist.


Gesendet: Donnerstag, 24. Mai 2012 09:35
An: Norman Geist
Betreff: Re: AW: namd-l: Generating force field for novel molecules


Hi Noramn

Thanks a lot for your appreciation. Basically I work with CHARMM; but I have no problem switching to AMBER, since NAMD supports that one too. I have done some MD simulations; but I'm new to the field of quantum chemistry. I'd be grateful if you provided me with some tutorials about the method you mentioned (using antechamber after gaussian). I found some tutorials on the antechamber website, but they're too specific and lack educational and explanatory fashion (I'm looking for something like NAMD tutorials which are so great). By the way, some keywords or web links would also work, since I don't want to bother you too much.

Best Regards
Mohammad Javad Aghaei
AmirKabir University of Technology
Tehran, Iran

P.S. It would also be so nice of you to share any ideas about generating CHARMM force-field parameters.

On Thu, 05/24/2012 08:45 AM, "Norman Geist" <> wrote:

Hi Mohammad,


for which force field you want to generate these parameters, that’s really important, as the procedure is mostly different. For amber one could easily use Gaussian or Games or the RED SERVER which provide both, and then put it through antechamber afterwards. For charmm there’s a different procedure. But I think you would find many tutorials for that on the net. If you already know that all, and the problem is about this special kind of molecules, please tell what the problem with it really is.


Norman Geist.


Von: [] Im Auftrag von MOHAMMAD JAVAD AGHAEI
Gesendet: Mittwoch, 23. Mai 2012 10:17
Betreff: namd-l: Generating force field for novel molecules


​Hi all

Does anyone have any experience in generating force field parameters for novel small molecules (e.g. morphine) using quantum mechanics softwares (semi-empirical or ab-initio).
If so, it would be so nice of them to share their experience.

Best Regards
Mohammad Javad Aghaei
AmirKabir University of Technology
Tehran, Iran

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