Polarization sensitive coherent Raman spectroscopy (PCARS/PCSRS) was applied to study proteins in solutions in both two and three color configurations. In off-electron resonant PCARS the main problem is the nonresonant background, arising from the solvent. The advantage of PCARS is the resolving power as is demonstrated in the amide-I region of some proteins. Three color PCSRS was used to measure independently the (chi) ⁽³) components of hemoglobin resonantly excited in the (alpha) and (beta) absorption bands. From a simultaneous fit on different PCSRS spectra vibrational parameters were determined including phases and depolarization ratios. Besides the polarization and phase characterization of hemoglobin bands, we decomposed the vibrational amplitudes and phases into electronic contributions. Together with amplitudes, the phases contain information on electronic enhancement, vibronic coupling and symmetry of the molecular vibrations.

Date Published: 17 June 1993
PDF: 12 pages
Proc. SPIE 1922, Laser Study of Macroscopic Biosystems, (17 June 1993); doi: 10.1117/12.146183

Published in SPIE Proceedings Vol. 1922:
Laser Study of Macroscopic Biosystems
Jouko E. Korppi-Tommola, Editor(s)