Hello Jesse (and all others who may be interested in this topic)

I am sorry I took so long to reply to your post at:
http://groups.yahoo.com/group/spectroscopy/message/37
dated May 11, 1999, but I only found and joined this group today!
It has been decades since I worked in spectroscopy, but I hope to
find time to poke in here, now and then, to see what is happening.

You may well be the World's Leading Expert on density matrix methods
after lo, these many years, but since you had no replies, I thought I
would make a couple of suggestions to those interested in this topic.

My 1974 printing of "Statistical Mechanics: A Set of Lectures" by the
very famous R. P. Feynman devotes chapter 2 to density matrices.
Amazon describes the current version of the book here:
http://www.amazon.com/exec/obidos/ASIN/0201360764/

A book that is more germane to optical spectroscopy is "Fundamentals
of Quantum Electronics" by R.H. Pantell and H.E. Puthoff, both of
Stanford at the 1969 publication of the book by John Wiley & Sons.
They treat N-level systems using the density matrix in chapter 1,
which forms the basis for all else they do in the book. The
publisher's Web site (cf. http://www.wiley.com/remsearch.cgi?
query=Fundamentals+of+Quantum+Electronics&field=keyword ) seems to be
ignorant that the firm ever published this work and Amazon is none
the wiser as to its existence. Perhaps a used book dealer might find
you a copy - or you can contact one of the authors.

Dr. Ron Feigenblatt