Subject: Re: CCL:MOPAC93 alkali metal parametrization

From: [email-masked] (Henry Rzepa) (Henry Rzepa)
Date: Fri, 4 Feb 1994 15:43:42 +0000

>Dear netters,
>
>sorry for the last empty message (a bug caused by our elm-system).
>I hope your attention will still be existing today.
>
>My last question was:
>Does anybody know about papers dealing with MOPAC-parametrisation of
>alkaline, earth-alkaline (or transition) metals (ions or pure metals),
>which are not yet included in MOPAC93 ?
>
>In history of semiempirical calculation the right representation of
>ions (mostly electrostatic behaviour) was oversimplified. In some case
>these ions were reduced to point charges, on the other hand much too high
>charge transfer towards the ions was calculated.
>
>Thank you in advance.
>
>Mathias Brock
>[email-masked]
>

We have a paper about to appear in the March issue of Perkin Trans
2 (see http://www.ch.ic.ac.uk/rzepa/RSC/P2/3_07186C.html) dealing
with those monovalent ions currently parameterised in MNDO, and PM3
(ie Li, Na, K, Ga etc) and comparing with LAN1DZ/ECP ab initio
calculations. Basically, Na, K and Ga appear to have significant
problems with energies if not with geometries.

Dr Henry Rzepa, Dept. Chemistry, Imperial College, LONDON SW7 2AY;
[email-masked] via Eudora 2.01, Tel:+44  71 225 8339, Fax:+44 71 589 3869.
>From June '94: (44) 171 584 5774, Fax: (44) 171 584 5804
http://www.ch.ic.ac.uk/rzepa.html