Photoionization of Methane: Ionization Potential and Proton Affinity of CH4
- 15 May 1971
- journal article
- research article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 54 (10), 4256-4259
- https://doi.org/10.1063/1.1674669
Abstract
The relative photoionization cross section of methane has been measured at room temperature and at liquid‐nitrogen temperature. The data show that the ionization potential of methane is 12.615 ± 0.010 eV or lower. This result is discussed and compared with those obtained by photoelectron spectroscopy. The photoionization‐efficiency curve of CH5 + was also measured and found to have the same threshold as that of CH4 +. This observation sets a lower limit on the proton affinity of methane, namely PA(CH4) ≥ 5.46 eV. Consideration of other data supports the value PA(CH4) = 5.50−0.05 +0.20 eV.Keywords
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