Letter | Published:

Formation of Mercury Molecules

Naturevolume 135pages9991000 (1935) | Download Citation



IT has long been known that mercury vapour is ionised by photons having energies considerably less than that corresponding to the ionisation potential of the mercury atom. Rouse and Giddings1 showed in 1926 that mercury vapour is ionised by its resonance radiation, 2537 A. To explain this effect, Houtermans2 suggested that an excited atom in the 23P1 state of 4·9 volts energy may combine with a metastable atom in the 23P0 state of 4·7 volts energy to form an ionised molecule and a free electron. The energy available for ionisation of this molecule is (4·9 + 4·7) volts plus the heat of dissociation of the neutral molecule, which Winans3 gives from band spectra data as 0·15 volt, making a total energy of 9·75 volts.

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  1. 1

    Rouse and Giddings, Proc. Nat. Acad. Sci., 12, 447; 1926.

  2. 2

    Houtermans, Z. Phys., 41, 619; 1927.

  3. 3

    Winans, Phys. Rev., 37, 897; 1931.

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  1. The University, St. Andrews

    • F. L. ARNOT
    •  & J. C. MILLIGAN


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