Absorption cross sections, saturated vapor pressures, sublimation energies, and evaporation energies of some organic laser dye vapors

A new technique of transmission measurement of overheated dye vapors is applied to determine absolute absorption cross-section spectra of three active dyes for vapor phase dye lasers. The investigated compounds are 1,4-di[2-(5-phenyloxazolyl)]-benzene (POPOP), 1,4-di[2-(4-methyl-5-phenyl-oxazolyl)]-benzene (dimethyl-POPOP), and 2,5-diphenylfuran (PPF). The vapor absorption spectra are compared with liquid solution spectra in order to obtain information on the dye–solvent interaction. The saturated vapor densities are determined by transmission measurements after knowing the absolute absorption cross-section spectra. The latent heats of sublimation, evaporation, and melting are derived by analyzing the dependences of the saturated vapor densities on the vapor temperature.