Subject: ONIOM Frequency Calc with External program

From: Ralf Tonner <Tonner _()_ chemie.uni-marburg.de>
Date: Mon, 18 Apr 2005 12:16:21 +0200

Dear all,

we try to carry out some frequency calculations with
Gaussian03 (Rev. C02) using the ONIOM scheme.
Calculating pure G03-frequencies is no problem
(e.g. B3LYP/6-31G(d):HF/STO-3G).

Now we try to use an external program for the
high level calculation of the model system:
>...
> ONIOM(External:HF/STO-3G)
>freq
>...

and G03 gives the output-message:
>...
> External calculation of energy, first and second
derivatives.
> MO and density RWFs will be updated without
deorthogonalization.
> Numerical evaluation of force-constants.
>...

The manual states with the ONIOM-keyword, that "Energies, 
gradients and [analytic] frequencies" are available.
Is there a way to calculate analytic second derivatives
using an external program in G03 ?

Any suggestions are very welcome.
Thanks in advance

Ralf

--
Ralf Tonner
Philipps Universitdt Marburg
  Fachbereich Chemie
  AK Frenking
Hans-Meerwein-Stra_e
35032 Marburg
Germany

Tel.: +49-6421/28-27030
Tonner _()_ chemie.uni-marburg.de