Specifying QM/MM system

ilya ily... at gmail.com
Thu Oct 9 15:24:43 UTC 2008



On Oct 9, 5:52 pm, Laino Teodoro <teodor... at gmail.com> wrote:
> Ciao Ilya,
>
> may I answer your question with an additional provocative question?
> Where did you get the starting geometry of your system?
> Is it properly thermalized?
>
> The idea behind QM/MM is to have always a fully working MM calculations,
> that you can switch to a QM/MM.
> You need it for several reasons.. one for all.. you need a  
> thermalized structure
> and QM/MM is still too far slow to thermalize properly a system (i.e.  
> run
> 0.1-1 ns of NVT).
>
> So.. I highly suggest you, first, to have a working MM setup.. then  
> you can switch
>   to QM/MM.

I know that... Just tried to get QM/MM working and understand how it's
working.

>
> Just to sweep away all the doubts.. charges for QM atoms, though  
> requested are
> never used. The only classical contribution coming from QM atoms are  
> the QM-MM
> non-bonded.
>
> Cheers
> Teo
>

Thanks, that's good.

Ilya.



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