Fluorescence yield from photodissociation of CH4 at 1060–1420 Å

Abstract

The photoabsorption and fluorescence cross sections of CH4 were measured using synchrotron radiation at 1060–1420 Å. The fluorescence starts to appear at 1330 Å, and its cross section increases with decreasing photon wavelengths. The fluorescence cross section at 1060 Å is 0.38×10−18 cm2, which is much smaller than the theoretical expectation. It is unlikely that the CH2 production from CH4 photodissociation will have a population inversion in the singlet system. A vibrational structure observed at 1060–1120 Å is probably the 1t2→3p Rydberg transition of CH4.