Excited states and thermalization distances of photons created by VUV photoionization of pure liquid alkanes

Excited states are detected in the VUV photoionization spectra of cyclohexane and dimethyl-2-2-butane. Some of the discernible peaks of cyclohexane can be assigned as belonging to the Rydberg series observed in the gas phase. The spectra structures of liquid (photoionization) and gaseous (absorption) D-2-2-B are also comparable. The ionization quantum yield and thermalization range parameter of D-2-2-B were determined up to 2 eV above the ionization threshold of liquid D-2-2-B. Comparison with the values of the same parameters when quenchers are present seems to indicate that quenchers interact more with the excited states than with epithermal electrons.<>