Subject: CCL: electronic overlaps at different configurations

From: Dr Seth OLSEN <s.olsen1 |a| uq.edu.au>
Date: Thu, 09 Jun 2005 13:14:17 +1000

Hi CCLers,

I'm curious about what it would take to calculate products of electronic
state overlaps at neighboring geometries that look like:

  <psi(r1)>|psi(r2)><psi(r2)|psi(r3><psi(r3)|psi(r1)>

where psi is an electronic wavefunction of a given adiabatic state over
all degrees of freedom, or alternatively

<psi(r1)| P(r2)P(r3) |psi(r1)>

where P(ri) are density operators for a given electronic adiabatic state.  

Particularly, I'm curious to know how one would go about doing this with
an electronic wavefunction defined in the usual 'ab initio' way, as sums
of configurations over molecular orbitals defined in an atom-centered
gaussian basis set.  Even without bulk rotations (in the sense that the
directions of the eigenvectors of the rotational inertial don't change)
and translations (that is, the neighboring points are different vectors
in the internal nuclear coordinate space), it seems it wouldn't be
straightforward due to the parametric dependence of the electronic basis
on the nuclear configuration.  For example, if the symmetry group
changes between configurations.

Can someone point me the direction of references that might relate to
this problem?

Cheers,

Seth

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Dr Seth Olsen, PhD
Postdoctoral Fellow, Computational Systems Biology Group
Centre for Computational Molecular Science
Chemistry Building,
The University of Queensland
Qld 4072, Brisbane, Australia

tel (617) 33653732
fax (617) 33654623
email: s.olsen1 |a| uq.edu.au
Web: www.ccms.uq.edu.au 

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