Anne Myers of the University of Rochester is supported by the Experimental Physical Chemistry Program in her continuing studies in which she uses resonance Raman and fluorescence spectroscopies to characterize the coupling of electronic transitions of a chromophore to nuclear degrees of freedom in the surrounding environment in liquids and amorphous solids. Three types of experiments will be carried out: (i) Raman linewidths for molecular ions will be compared under resonant vs. nonresonant excitation conditions to test the hypothesis that the previously observed increase in linewidth on resonance is due to coupling of the chromophore-localized vibrations to solvent or intermolecular phonons; (ii) resonantly excited emission spectra will be measured as a function of temperature and the spectra will be modeled to better understand the temperature dependence; (iii) low-temperature fluorescence line-narrowing spectra will be measured in chromophore/matrix combinations to investigate the chromophore dependence of the coupled phonon frequencies and coupling strengths. These investigations will provide insight to the processes that are responsible for the broadening of electronic absorptions in condensed media and to processes that affect chemical reaction rates in condensed phases. Efforts to develop practical optical memory devices based on persistent spectral hole burning in solids will be aided by a better understanding resulting from this research.
