Vibrational spectroscopy of anions by stimulated Raman pumping–photoelectron spectroscopy

The first demonstration of a technique for the vibrational spectroscopy of anions, stimulated Raman pumping-anion photoelectron spectroscopy is reported. It combines the high spectral resolution of stimulated Raman pumping with the high detection efficiency, mass-selectivity, and wide applicability of anion photoelectron spectroscopy. The vibrational spectrum of a test system, C2−, is recorded and the frequency of the 1←0 vibrational transition is determined to be 1757.8±0.1 cm−1. The Q-branch is partially rotationally resolved.