The photoionization spectrum of the threshold region of equilibrated at room temperature has been recorded and compared to the zero electron kinetic energy (ZEKE) spectrum of Blush et al. [J. Chem. Phys. 98, 3557 (1993)]. The ionization onset region is at higher energy than previous high-temperature photoionization work [Chupka and Lifshitz, J. Chem. Phys. 48, 1109 (1967)], but still lower than that implied by invoking only direct ionization. The residual discrepancy can be accounted for by including fully allowed quadrupole-induced and partially allowed dipole-induced rotational autoionization, thus making the observed onset completely congruous with the ZEKE ionization potential. In addition, the fragment appearance potential of from was redetermined by accurate fitting as With the very precise ZEKE ionization potential, this yields the best current value for the bond dissociation energy in methane, ( at 298 K).
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Research Article| December 15 1997
Evidence of rotational autoionization in the threshold region of the photoionization spectrum of
Maritoni Litorja, Branko Ruscic; Evidence of rotational autoionization in the threshold region of the photoionization spectrum of . J. Chem. Phys. 15 December 1997; 107 (23): 9852–9856. https://doi.org/10.1063/1.475282
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