Ionization Detection Of Stimulated Raman Spectra

Ionization-detected stimulated-Raman spectroscopy(IDSRS)1 is a new technique for high-sensitivity, high-resolution Raman studies. The technique is based on resonant laser ionization detection of vibrationally-excited molecules produced via stimulated Raman pumping. In this paper we illustrate the sensitivity of IDSRS relative to stimulated Raman gain spectroscopy by comparing spectra taken of the diatomic molecule NO using each technique. We then present more recent results on the application of IDSRS to a considerably larger molecule, benzene. These spectra, taken near 1600 cm-1, cover the region where the v16 fundamental and v2+v18 combination band of benzene overlap to produce a particularly complex appearing spectrum. By taking advantage of the double-resonance capabilities of IDSRS, we are able to cleanly separate the contributions of each vibrational band and thereby greatly simplify their spectra.