Resonance multiphoton ionization study of the B-1 Sigma(+) state of CO

Abstract

We report measurements of (4+2) resonantly enhanced multiphoton ionization (REMPI) of CO. The excitation route is first to the nu=0 level of the CO B (1)Sigma(+) state followed by the absorption of additional two photons to reach the ionization continua. Measurements of the CO+ and C+ ion intensities as a function of the wavelength were made, yielding no rotational structure of any intermediate resonant state in contrast to the (2+1) REMPI experiment. In a second measurement, the laser frequency was set at the upsilon=0 band head of the B (1)Sigma(+) and the kinetic-energy spectrum of the ejected electrons was measured. The observed photoelectron spectrum is assigned to the multiphoton ionization of CO via the resonant X (1)Sigma(+) to B (1)Sigma(+) excitation.