The multiphoton ionization spectrum of jet-cooled pyrimidine in the 3p Rydberg and 3B1 (π∗,n) states

Resonance-enhanced multiphoton ionization (REMPI) has been applied to study the n → 3p Rydberg transition of pyrimidine (jet-cooled sample and mass resolved spectrum). Only the one component, the 3pz(B2), appears in the (2 + 1) REMPI and the active vibrations are ν6a = 622, ν1 = 946, and ν9a = 1116 cm−1. The symmetry of the state was determined by polarization measurements (linear, circular polarization). The first (π∗,n) 3B1 triplet state appears as a one-photon resonance in the three-photon ionization process.