Resonant Laser Excitation of Potassium Vapour: Experimental Investigation of Energy-Pooling Collisions and Plasma Production

The illumination of potassium vapour by means of a c.w. dye-laser resonant with the fundamental 4S--~ 4_/' transitions results in the excitation of high-lying atomic and molecular states. In the present paper we report a spectroscopic study of this phenomenon and experimental evidence that the mechanisms responsible for the population of some of the levels not directly excited by the laser involve the creation of a plasma in the vapour.