Resonance-enhanced multiphoton ionization of jet-cooled 2-methylfuran

Mass-resolved, resonance-enhanced multiphoton ionization (REMPI) spectra of jet-cooled 2-methylfuran have been measured in various spectroscopic regions (visible and UV ns dye laser). The results have been interpreted as two-photon resonances and as three-photon resonances to the 3d Rydberg manifold chiefly. The 3d 1A1←(X∼)A1 transition, located at 56,360 cm−1, is the strongest one in the (2 + 1) REMPI spectrum and has a discrete vibrational structure. The vibrational analysis has been performed. The three-photon resonance spectrum tracks the 3d VUV absorption spectrum. The strongest transition in this case is the 3d 1B2←(X∼)A1 transition located at 56,013 cm−1. The transition to the 3s A2 Rydberg state has been detected at 44,018 cm−1 (3 + 2 REMPI spectrum).