Oscillation on the Ultraviolet Bound-Free Continua of Diatomic Molecular Xenon and Molecular Krypton



The initial proposal for the use of molecular bound-free transitions in laser systems was advanced by Houtermans 1 in 1960 in relation to the continua of H2 and Hg2. In spite of this early suggestion, only relatively recently has genuine stimulated emission been observed on transitions of this type on the ultraviolet molecular continua of xenon2 at ~1722 A and krypton3 at ~1457 Å. We note that the rare gas molecular continua represent a subset of the much larger class of bound-free systems. Some additional members of this more extensive group are the examples4–7 Zn2, Cd2, Hg2, HeH, NeH, and LiXe. Among the simplest systems representing the general properties of molecular bound-free transitions. and for which there exists a considerable literature is He2. A partial energy level diagram representative of this class of molecular systems is illustrated in Fig. (1). The essential property is that some of the upper states have a potential minimum at an internuclear separation Ro for which the ground state curve is strongly repulsive. Provided that a kinetic mechanism exists for population of the upper bound states, the repulsive character of the ground level enhances the tendency for the production of large population inversions in the Franck-Condon region around Ro.


Relativistic Electron Beam Internuclear Separation United States Atomic Energy Commission High Current Relativistic Electron Beam Repulsive Character 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    F. G. Houtermans, Helv, Phys. Acta 33, 933 (1960). Other analyses of the continua of H2 have1been discussed in the following: For the H2 a3+ g → b3+ u transition see A. J. Palmer J. Appl. Phys. 41, 4328 (1970); C.V. Heer, J. Appl. Phys. 41, 1875 (1970). For the molecular continuum of Hg2 see D. A. Leonard, J. C. Keck, and M. M. Litvak, Proc. IEEE 2h, 1785 (1963); R. J. Carbone and M. M. Litvak, J. Appl. Phys. 39., 2413 (1968); D. C. Lorents, R. J-f. Hill, and D. J. Eckstrom, Molecular Metal Laser, Stanford Research Institute Report, November 27, 1972; R. M. Hill, D. J. Eckstrom, D. C. Lorents, and H. H. Nakano, Measurements of Negative Gain for Hg e Continuum Radiation,to be published; D. J. Eckstrom, R. M. Hill, D. C. Lorents, and H. H. Nakano, Collisional Quenching and Radiative Decay of the Mercury Excimer, to be published.Google Scholar
  2. 2.
    N. G. Basov, V. A. Danilychev, and Yu. M. Popov, Sov. J. Quant. Elec. 1, 18 (1971); H. A. Koehler, L. J. Ferderber, D. L. Redhead: and P. J. Ebert, Appl. Phys. Letters 21, 198 (1972); P. W. Hoff, J. C. Swingle, and C. K. Rhodes, Demonstration of Temporal Coherence, Spatial Coherence, and Threshold Effects in the Molecular Xenon Laser, UCRL-7 665, Opt. Commun., to be published; J. B. Gerardo and A. Wayne Johnson, High Pressure Xenon Laser at 1730 Å, to be published, Preliminary calorimetric studies were reported in A. C. Kolb, N. Rostoker, R. White, K. Boyer, R. Jensen, P. Robinson, and A. Sullivan, Bull. Am. Phys. Soc. 17, 1031 (1972). Line narrowing with unexplained structure has also observed, R. Jensen, private communication.CrossRefGoogle Scholar
  3. 3.
    P. W. Hoff, J. C. Swingle, and C. K. Rhodes, Observation of Stimulated Emission from High Pressure Krypton and Argon/Xenon Mixtures, UCRL-7 715, Appl. Phys. Letters, to be published.Google Scholar
  4. 4.
    For data on the continua of Zn2, Cd2, and Hg2, as well as a general discussion of the early work on continuous spectra, see Wolfgang Finkelnburg, Kontinuierliche Spektren (Springer-Verlag, Berlin, 1938).Google Scholar
  5. 5.
    HeH is discussed in C. A. Slocomb, W. H. Miller and H. F. Schaefer III, J. Chem. Phys. 55, 926 (1971).ADSCrossRefGoogle Scholar
  6. 6.
    The potential curves of HeH are considered in V. Bondybey, P. K. Pearson, and H. F. Schaefer III, J. Chem. Phys. 57, 1123 (1972).ADSCrossRefGoogle Scholar
  7. 7.
    The LiXe molecule is discussed in W. F. Baylis, J. Chem. Phys. 51, 2665 (1969).ADSCrossRefGoogle Scholar
  8. 8.
    The molecular properties of the He2 system are discussed in Marshall L. Ginter and Rubin Battino, J. Chem. Phys. 52, 4469 (1970) and further references cited therein. Recent experimental data on He2 are described by W. A. Fitzsimmons in Atomic Physics 3, edited by S. J. Smith and G. K. Walters (Plenum Press, New York, 1973) p. 477.ADSCrossRefGoogle Scholar
  9. 9.
    E. V. George and C. K. Rhodes, UCRL-74516, Kinetic Model of Ultraviolet Inversions in High Pressure Rare Gas Plasmas, Appl. Phys. Letters, to be published. Another analysis has been given by D. C. Lorents and R. E. Olson, Excimer Formation and Decay Processes in Rare Gases, Stanford Research Institute Report, December 1972. Also see Charles K. Rhodes, Review of Ultraviolet Lasers, UCRL-74816, to be published.Google Scholar
  10. 10.
    Martin J. Berger and Stephen M. Seltzer, Tables of Energy Losses and Ranges of Electrons and Positrons, N65-12506 (NASA, Washington, D.C., 1964).Google Scholar
  11. 11.
    Of course, there are many possible dimer states. For a discussion of the structure of xe2 see R. S. Mulliken, J. Chem. Phys. 52, 5170 (1970).Google Scholar
  12. 12.
    R. Boucique and P. Mortier, J. Phys. D3, 1905 (1970).ADSGoogle Scholar
  13. 13.
    D. Smith, A. G. Dean, and I. C. Plumb, J. Phys. B5, 2134 (1972).ADSGoogle Scholar
  14. 14.
    H. J. Oskam and V. R. Mittelstadt, Phys. Rev. 132, 1445 (1963).ADSCrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1974

Authors and Affiliations

  1. 1.Lawrence Livermore LaboratoryUniversity of CaliforniaLivermoreUSA

Personalised recommendations