Methane photoelectron spectrum

The photoelectron spectrum of methane shows two bands, at 23 and 14 eV, and not the single band we would expect from the equivalency of the four C—H bonds. The reason is that ordinary sp hybridization is not adequate to explain phenomena involving ionized molecules (such as the CH4" radical ion, which is left behind when an electron is ejected from methane). For these phenomena it is... 

Energy Levels for Hole Injection. For the hole conductor TPD (6), measurements are available from different groups that allow a direct comparison of different experimental setups. The ionization potential that corresponds to the HOMO level under the assumptions mentioned above was measured by photoelectron spectroscopy to be 5.34 eV [230]. Anderson et al. [231] identified the onset of the photoelectron spectrum with the ionization potential and the first peak with the HOMO energy, and reported separate values of 5.38 and 5.73 eV, respectively. The cyclovoltammetric data reveal a first oxidation wave at 0.34 V vs. Fc/Fc+ in acetonitrile [232], and 0.48 V vs. Ag/0.01 Ag+ in dichloro-methane [102], respectively. The oxidation proceeds by two successive one-electron oxidations, the second one being located at 0.47 V vs. Fc/Fc+. 

T.X. Carroll, N. Berrah, J. Bozek, J. Hahne, E. Kukk, L.J. Saethre, T.D. Thomas, Carbon Is photoelectron spectrum of methane Vibrational excitation and core-hole lifetime, Phys. Rev. A 59 (1999) 3386. 

The photoelectron spectrum of methane shows two bands,at 23 and 14 eV, and not the single band we would expect from the equivalency of the four C—H... 

Figure 21. The inner valence Auger effect in formaldehyde (methanal). The broad peak in the regular photoelectron spectrum near 34 eV is an inner valence (IV) band based on C2s ] ionization. It recurs as a peak in the electron distribution for double photoionization and in the quantum yield. The uppermost curve shows the spectrum of HCH02+, where the ground state is strongly populated by this effect. 

Pauling argued that the photoelectron spectrum of methane is consistent with sp hybridization for methane. Pauling, L. /. Chem. Educ. 1992,69,519. See also the discussion by Simons, ]. J. Chem. Educ. 1992, 69, 522. 

Photoelectron spectrum of methane. [Reproduced by permission, Mike Prushan.]... 

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