You all didn't look too convinced by my description about RAMAN modes. This might help... http://www.doitpoms.ac.uk/tlplib/raman/active_modes.php -- Andrew J. Pounds, Ph.D. (pounds_aj at mercer.edu) Professor of Chemistry and Computer Science Mercer University, Macon, GA 31207 (478) 301-5627 http://faculty.mercer.edu/pounds_aj