Hi,
You cannot use the Gaussian optimizer since it is sander that masters
what happens to the coordinates (from a coordinate set, sander asks
gaussian to compute an energy, it does not let gaussian modify them,
hence the "force" keyword).
You'd better use one of the optimizers available in sander (&cntrl
namelist) instead.
Gerald.
On 06/13/2014 11:16 AM, Kshatresh Dutta Dubey wrote:
> Dear Users
>
> I am using Amber 14 for QM/MM calculation with Gaussian as external
> interface. I have to optimize a system containing some amino acids and a
> ligand in QM regions. I found that Amber automatically adds some keywords
> in route section of Gaussian input that force Gaussian to do single point
> calculations. For example, I used :
> *&gau*
> * mem = '2GB'*
> *! method = 'B3LYP',*
> *! basis = '6-31G',*
> * use_template =1,*
> * num_threads = 2*
> * /*
> for &gau namelist and :
>
> *#P OPT B3LYP/6-31G SCF=(Conver=8)*
>
> for template file namelist. The calculations runs fine and it shows normal
> termination, but I found that it does only single point calculation not
> optimizing the structure while I have mentioned optimization in route
> sections. I notice that Amber adds some additional keyword such as 'Force'
> in route section which restricts Gaussian to calculate forces only. I guess
> it is fine for QM-MM/MD since we need forces for dynamics, but here I am
> interested in QM/MM optimization only. The route section modified by Amber
> is :
>
> *#P OPT B3LYP/6-31G SCF=(Conver=8) NoSymm Force Guess=Read Charge Prop=*
> * (Field,Read)*
>
> How can I disable 'Force' keyword so that I can perform proper
> optimization. I will be thankful for your help.
>
> thanks
>
--
____________________________________________________________________________
Prof. Gerald MONARD
SRSMC, Université de Lorraine, CNRS
Boulevard des Aiguillettes B.P. 70239
F-54506 Vandoeuvre-les-Nancy, FRANCE
e-mail : Gerald.Monard.univ-lorraine.fr
tel. : +33 (0)383.684.381
fax : +33 (0)383.684.371
web : http://www.monard.info
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Received on Fri Jun 13 2014 - 03:00:02 PDT
