Multiphoton Ionization of Molecular Cesium with a Tunable Dye Laser

This paper reports the observation of the two-photon ionization of molecular cesium as a continuous function of laser wavelength in the 6200-6600-Å region with a tunable dye laser having a 0.18-Cm^-1 linewidth. To the author's knowledge, it serves to illustrate the first extension to neutral molecular species of the important techniques of resonant multiphoton photodetachment spectroscopy. The resulting two-photon photoionization spectrum is intepreted in terms of the vibrational structure of the resonant intermediate molecular state.