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Excitation Processes in Molecular Nitrogen

Nature volume 162, pages 231232 (07 August 1948) | Download Citation



IN controlled electron experiments it has been usually assumed1 that in the emission of the triplet bands of molecular nitrogen, transitions to the upper levels of the band systems concerned come about directly as a result of collisions of the first kind between molecules in the ground-state X1Σ+g and fast electrons. A further assumption made is that the energy values of the upper states of the bands concerned are the voltages at which they respectively appear when excited by an electron beam of controlled energy. These assumptions lead to the placing of the triplet-levels approximately 2 volts higher than the normally accepted values based on reliable spectroscopic evidence 2. In particular, the A3Σ-+u level would be placed about 2 volts above the value suggested by the analysis of the Vegard - Kaplan bands.

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  1. 1.

    , Astrophys. J., 62, 145 (1925). , Z. Phys., 34, 622 (1925). and , Proc. Roy. Soc., A, 147, 584 (1934). , Proc. Roy. Soc., A, 146, 166 (1934); 150, 371 (1935). , Geofys. Pub., 12, No. 12, 1 (1940).

  2. 2.

    , Phys. Rev., 69, 362 (1946). , "Dissociation Energies", 155 (1947).

  3. 3.

    , loc. cit.

  4. 4.

    and , "The Theory of Atomic Collisions", 192.

  5. 5.

    , Nature, 161, 283 (1948).

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  1. Imperial College of Science and Technology, London

    • R. W. NICHOLLS


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