Subject: Re: CCL:fractional nuclear charge

From: Mikael Johansson <mpjohans^at^pcu.helsinki.fi>
Date: Thu, 6 Nov 2003 11:37:21 +0200 (EET)

Hello Steve and All!

On Wed, 5 Nov 2003, Steve Williams wrote:

> I have a colleague who would like to some quantum chemistry calculations on
> the following system: R-OH+  --> R-NH, that is, a smooth transition from an
> open shell alcohol radical cation to a neutral radical amide.  Is there a
> way to do this?  We discussed several options, based on what we have here:

> 3) Is there existing code out there that already does this?

With Turbomole (http://www.turbomole.com) you can do this. Or, I should
say, you can at least define a fractional nuclear charge, and Turbomole
performs the calculation. I tried HF, DFT and RI-MP2 on N2 with one of
the N's having a q of +6.5.

The basis set might be a problem, as they are optimised for specific
atoms. I guess one way of getting around this would be to use a combined
basis set for the metamorphosing atom, consisting of the BS of both
the initial (O) and the final (N) atoms.

Have a nice day,
    Mikael Johansson
    University of Helsinki
    Department of Chemistry
    mikael.johansson^at^helsinki.fi
    http://www.helsinki.fi/~mpjohans/
    Phone: +358-9-191 50185
    FAX  : +358-9-191 50169