Unimolecular reaction kinetics in the high-pressure limit without collisions.
Molecular activation by blackbody photons, first postulated in 1919 by Perrin, plays a dominant role in the unimolecular dissociation of large ions trapped at low pressure in a Fourier-transform mass spectrometer. Under readily achievable experimental conditions, molecular ions of the protein ubiquitin equilibrate with the blackbody radiation field inside the vacuum chamber. The internal energy of a population of these ions is given by a Boltzmann distribution. From the temperature dependence of unimolecular dissociation rate constants measured in the zero-pressure limit, Arrhenius activation parameters equal to those in the high-pressure limit are obtained.
Department of Chemistry, University of California, Berkeley, California 94720, USA.
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Price
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Schnier
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Jockusch
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Strittmatter
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Williams