Energy Transfer from Electron-beam Excited Argon to Nitrogen and Popop Dye Vapor

Since the first observation of electron-beam excited superradiant emission from the organic dye POPOP in the vapor phase buffered by high-pressure pure argon [1 ] , there has been considerable interest in developing this system into an efficient and powerful UV-visible tunable laser [2,3]. In order to establish optimum electron-beam excitation conditions for the organic dye vapor-buffer gas mixture, an understanding of possible energy-transfer processes is necessary. In the present work the energy-transfer processes of Ar-POPOP have been studied and compared to the well-known formation kinetics scheme of A r N 2 [4,5]. The species responsible for channeling electron-beam energy into the upper singlet levels of POPOP has been identified, and a number of pertinent reaction rate constants for various energy-transfer processes have been estimated. In addition, a hitherto unreported quenching mechanism in the A r N 2 system has been identified. 2. Experimental