Subject: G98 TD/CIS Opposite sign of the components of length- and velocity dipole moments?

From: Peter Waaben Thulstrup <[email-masked]>
Date: Tue, 04 Jun 2002 14:34:08 +0200

Dear CCL,

I have some questions regarding the output os CIS and TD jobs in G98
(Rev. A7). I can't find anything on these issues in Gaussian
documentation or past CCL posts, although the questions are rather
simple. So I hope it makes sense...

The output of TD and CIS calculations give the x, y, and z components of
the "Ground to excited state Transition electric dipole moments",
"Ground to excited state transition velocity dipole Moments", and the
"Ground to excited state transition magnetic dipole Moments". 

1) Why are the components of the electric and velocity derived
transition dipole moments oppositely signed? I thought that they should
be identical in a complete basis. I would have thought that the sign
ought to be the same. Which values should I trust? 

2) Is it possible to say which of the computed oscillator strengths
(dipole-length or dipole-velocity derived) provide the best estimate of
experimental absorption intensities?

3) I suppose that the computed electric and magnetic dipole moments are
origin dependent. But are the magnetic transition dipole moments derived
in a manner which make them related in to the transition velocity dipole
moments, rather than the transition electric dipole moments? (e.g. in
terms of origin dependence etc.)

Any help or comments will be greatly appreciated!

Peter 
-- 
Peter W. Thulstrup
Chemistry Department / Royal Veterinary and Agricultural University
Thorvaldsensvej 40 / DK-1871 Frederiksberg C / Denmark
Phone: +45 35282464 / Fax: +45 35282398 / E-mail: [email-masked]