Irikura, K.
(1999),
The Ionization Energy of CF<sub>3</sub>: When Does Entropy Matter in Gas-Phase Reactions?, Journal of the American Chemical Society
(Accessed April 29, 2024)
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The Ionization Energy of CF3: When Does Entropy Matter in Gas-Phase Reactions?
Published
Author(s)
Abstract
A minor controversy has emerged recently over the value of the ionization energy of the trifluoromethyl radical, CF3. Apparently solid evidence supports both high values, IEa {nearly equal to} 9.05 eV, and low values, IEa {nearly equal to} 8.65 eV. Examining the assumptions made in the analysis of the various experimental results shows that the root of the discrepancy is the role of entropy in low-pressure, gas-phase ion chemistry. The proper treatment of entropy has itself been a more fundamental controversy for a long time. In the zero-pressure limit, conservation of energy (δE) of a molecular collision is the primary consideration, but at the high-pressure limit the free energy (δG) dictates the outcome of a reaction: what pressures qualify asCitation
Journal of the American Chemical Society
Volume
121
Issue
No. 33
Pub Type
Journals
Keywords
entropy, free energy, ion chemistry, ionization energy, photoionization
Citation
Created September 1, 1999, Updated February 17, 2017