The Quenching of Mercury Resonance Radiation. II. The Production of Metastable (3<i>P</i>0) Atoms

Mercury atoms in the 63P0 state were produced from the Hg(63P1) state by collisions of the second kind with N2 under steady-state illumination with 2537 Å light in a static system. C2H4 was found to quench Hg(63P0) atoms, with a rate constant of 2.4 × 1013 cc mol−1·sec−1, forming excited C2H4 which decomposes to C2H2 and H2 with a mechanism similar to the Hg(63P1) photosensitized decomposition. The reduction in the yield of this reaction due to the addition of various gases was used to determine cross sections for the deactivation of Hg(63P0) atoms by H2, D2, CH4, C2H6, C3H8 CH3CD2CH3, c-C3H6, C(CH3)4, n-C4H10, and i-C4H10. The quenching cross sections relative to C2H4 are, respectively, 4.94 × 10−2, 4.72 × 10−2, < 1.0 × 10−5, 4.0 × 10−4, 3.9 × 10−3, 3.1 × 10−4, 1.8 × 10−4, 4.3 × 10−4, 6.8 × 10−3, and 2.2 × 10−2. Relative quenching cross sections for some of the preceding were obtained also from measurement of Hg(61P0) induced electron emission from Ag, and the results were in agreement with the first method. In general, Hg(63P0) reactions are similar in nature to other excited metal atom–molecule reactions. However, they exhibit much lower quenching cross sections and a more marked dependence on the strength of the C–H bond than do corresponding Hg(63P1) reactions. The inadequacy of simple models for quenching based solely upon conservation of total electronic angular momentum is discussed. The importance of both total excitation energy and C–H bond energy is shown by a comparison of the quenching cross section of Hg(63P0), Hg(63P1), andHg(61P1) by the alkanes.

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The Quenching of Mercury Resonance Radiation. II. The Production of Metastable (3P0) Atoms

Cited by 14 publications

References 9 publications

Isotopic Effects and the Mechanism of Energy Transfer in Mercury Photosensitization

Isotopic Effects and the Mechanism of Energy Transfer in Mercury Photosensitization

References

Quenching of Hg(63P) Atoms by Hydrogen and Hydrocarbons

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