Multiphoton transitions in gases at microwave frequencies

Multiphoton transitions are produced irradiating a gas by two microwave power sources. Three-photon transitions in NH 3 and OCS have been studied in function of frequencies, power and density of gases. Measurements agree fairly well with theoretical predictions Observation de transitions multiphotoniques en irradiant un gaz avec deux sources de rayonnement hyperfrequence. Etude des transitions a 3 photons de NH 3 et OCS en fonction de la frequence et de la puissance du rayonnement hyperfrequence, et de la densite des gaz. Bon accord avec les previsions theoriques