Laser Spectroscopy of Molecules in the Gas Phase: From Extreme Ultraviolet to Far Infrared Spectral Region

Three different types of laser molecular spectroscopy in the gas phase are presented. Firstly, the tunable coherent radiation generated in the extreme ultraviolet region is used to investigate the deexcitation mechanism in the highly excited states of H2 and D2. Secondly, the amplified spontaneous emission ranging from near- to far-infrared region exhibits the possibility of a new radiative relaxation channel among the highly-excited Rydberg states of NO. Finally, the application of the mid-infrared free electron laser to the studies of chemical reactions and molecular structure is described.