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Laser-Induced Unimolecular Reactions

  • N. Bloembergen
  • E. Yablonovitch
Conference paper
Part of the Springer Series in Chemical Physics book series (CHEMICAL, volume 6)

Abstract

The vibrational energy levels of a diatomic molecule are schematically shown in Fig.l. Due to anharmonicity they are not evenly spaced as they would be for a strictly harmonic oscillator. It is clear that the nearly even spacing is advantageous in reaching high vibrational excitation. For monochromatic excitation below the resonant frequency for the fundamental vibrational transition, the energy mismatch from real intermediate states is much smaller than in the electronic case. Nevertheless, the power level required for monochromatic radiation to excite a diatomic molecule, such as HF, to a level with fourteen vibrational quanta close to the dissociation limit is very high. It would be difficult to avoid dielectric breakdown of the gas. In fact, dissociation of a diatomic molecule by monochromatic infrared radiation has not been convincingly demonstrated. Perhaps some emphasis is needed to say that the interest is here focused on collisionless mechanisms. One can, of course, heat a molecular vapor to sufficiently high temperature so that collisionally induced dissociation sets in. It is possible to reach such temperatures by one-photon absorption processes in a c.w. laser beam, if the frequency corresponds to a strong absorption line of the molecular species.

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References

  1. [1]
    J.L. Hall and J.L. Carlsten, eds.: Laser Spectroscopy III, Vol. 7 in Optical Sciences ( Springer, Berlin 1977 )Google Scholar
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    J.H. Eberly and P. Lambropoulos, eds.: Multiphoton Processes ( Wiley, New York 1978 )Google Scholar
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    N. Bloembergen and E. Yablonovitch: Physics Today 31, 23 (1978)ADSCrossRefGoogle Scholar
  4. [4]
    R.V. Ambartsumian and V.S. Letokhov: in Chemical and Biochemical Applications of Lasers, Vol. 3, C.B. Moore, ed. (Academic Press, New York 1977) Ch. 2Google Scholar
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    P.J. Robinson and K.A. Holbrook: Unimolecular Reactions ( Wiley, New York 1972 )Google Scholar
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    H.S. Kwok: Ph.D. Thesis, Harvard University (1978); H.S. Kwok and E. Yablonovitch: submitted to Phys. Rev. Lett.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1979

Authors and Affiliations

  • N. Bloembergen
    • 1
  • E. Yablonovitch
    • 1
  1. 1.Division of Applied SciencesHarvard UniversityCambridgeUSA

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