Photoionization mass spectrometry of C₆₀ and C₇₀ with a vacuum ultraviolet hydrogen laser source

A time-of-flight mass spectrum of the C₆₀ and C₇₀ fnllerenes with the use of a vacuum ultraviolet H₂ laser photoionization source is presented. The photon energy is 7.8 eV, approximately 0.2 eV above the reported ion thresholds of both molecules. This relatively low excess energy is believed to be insufficient for fragmentation, as demonstrated by production of only parent ions.