Subject: inst. normal modes of solvents

From: [email-masked] (bittner)
Date: Fri, 9 Dec 1994 08:44:25 -0600 (CST)

Dear Fellow Netters:

I'm currently developing a theory for the effect of quantum coherences
between the solvent molecules and a solute particle during
non-radiative relaxation.  Even thought these coherences are very
transient (on the order of 10 fs at most in liquids at normal
temperatures) they play an important role in limiting coherent energy
exchange process through extended states.  I have two related
questions which I wish to pose to the simulation experts.

1.) Because the coherences are short, my theory assumes that an
instantaneous normal mode description of the solvent modes is
sufficient for my purposes.  A further approximation is that the
dispersion of frequencies, i.e. the normal mode spectrum, is
relatively insensitive to the electronic state of the solute molecule.
Is this reasonable and does any one have data that either supports or
refutes this claim?

2.) The next question is whether or not an ohmic type spectral model
provides a sufficient description of the solvent modes.  The
particular physical system that I have in mind is that of the
hydration of an excited charged ion in liquid water.

Thanks in advance and I hope this stirs up discussion.  Reply either
to me directly or to the net. I'll report the interesting replies.
Also, if someone wants a preprint of our work, I'd be happy to send
some out (as soon as the papers are submitted).

Regards, 
Eric R. Bittner

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    Eric R. Bittner                  phone:  (512)-471-1092
    Dept. of Chemistry                 fax:  (512)-471-8696
    Univ. of Texas 
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