Infrared laser multiple photon ionization

Abstract

The production of ions as a result of the interaction of intense CO₂‐ laser pulses with a variety of organic molecules is reported. The laser frequency dependence of the ionization follows closely the linear infrared absorption spectrum of the respective molecule. The extent of ionization depends very strongly on laser energy fluence. The ion‐production process is found to have a strongly collisional character. Various possible mechanisms of laser‐induced ionization are discussed, and evidence is presented favoring laser‐induced chemi‐ionization.