Subject: Re: singlet-triplet crossings...

From: David Gallagher <[email-masked]>
Date: Thu, 06 Jun 2002 07:16:53 -0700

Hi Roy,

Angalda and Bofill have developed a method for locating intersystem 
crossing geometries which is now incorporated into MOPAC 2002 and CAChe. 
The reference below may provide more insight, and there is additional 
information in the MOPAC manual at 
http://www.cachesoftware.com/techsupport/mopac/

J. M. Anglada and J. M. Bofill, "A Reduced Restricted-Quasi-Newton-Raphson 
Method for Locating and Optimizing Energy Crossing Points Between Two 
Potential Energy Surfaces", J. Comp. Chem., 1997, 18, 992-1003 (1997).

Regards,
David Gallagher

At 11:13 AM 6/5/2002 -0700, Roy Jensen wrote:
>All
>
>I would like to understand how states of different multiplicity are
>coupled together AND how to determine the probability of surface-crossing.
>
>Coupling is, I believe, a spin-orbit interaction. CASSCF can apparently
>optimize to a singlet-triplet crossing -- has anyone attempted this?
>I am aware of the work by Landau and Zener in the 1930s on surface
>crossing probabilities.
>
>Roy Jensen
>
><I will summarize to the List.>
>
>
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