Oscillation on the Ultraviolet Bound-Free Continua of Diatomic Molecular Xenon and Molecular Krypton
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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.
KeywordsRelativistic Electron Beam Internuclear Separation United States Atomic Energy Commission High Current Relativistic Electron Beam Repulsive Character
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- 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
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