(2+1) resonance-enhanced multiphoton ionization–photoelectron spectroscopy of the OH radical

Abstract

A (2+1) resonance-enhanced multiphoton ionization–photoelectron spectroscopy (REMPI-PES) study of the OH radical has been carried out in the two-photon energy region between 81 300 and 88 900 cm−1. Translationally and rotationally hot OH radicals are generated via photodissociation of hydrogen peroxide or formic acid. The known D 2Σ− (v′=0–2) and hitherto unobserved 3 2Σ−(v′=0) intermediate states in this region (at 81 815.8 and 87 643.7 cm−1 above the ground state) are shown to possess predominant Rydberg character. From the rotational structure in the REMPI spectrum physical parameters have been derived for these states.