Ionization yields, total absorption, and dissociative photoionization cross sections of CH4 from 110 to 950 Å

Absolute absorption and photoionization cross sections of methane have been measured with an accuracy of about 2% or 3% over most of the wavelength range from 950 to 110 Å. Also, dissociative photoionization cross sections were measured for the production of CH+4 , CH+3 , CH+2 , CH+, and C+ from their respective thresholds to 159 Å, and for H+ and H+2 measurements were made down to 240 Å. Fragmentation was observed at all excited ionic states of CH4.