The β Bands of Nitric Oxide

Abstract

As has been shown by the work of E. P. Lewis and of Strutt and Fowler, the spectrum of active nitrogen consists of three systems of bands (α β, and γ bands of Strutt and Fowler), of which only the α bands (part of the first positive nitrogen bands) appear if oxygen is carefully excluded. The investigations of Lewis, and later those of Strutt, indicated that the γ bands (third positive nitrogen bands) and βl bands are both due to the presence of small amounts of oxygen as nitric oxide. Dr. H. Sponer has recently shown (Sponer, NATURE, 117, p. 81, Jan. 16, 1926, and Sponer and Hopfield, Phys. Rev., 27, 640, 1926) that this is certainly true, and that the and systems have a common final state which is the normal state of NO. This is in agreement with the calculations of Birge and of Mulliken, which indicated that, with a certain assignment of quantum numbers, the vibrational constants for the final state are identical in the two systems. In a recent paper in the Philosophical Magazine (Sept. 1926, p. 621), Dr. R. C. Johnson and Mr. H. G. Jenkins give equations for the frequencies of the β system heads in terms of the vibrational quantum numbers. The proper assignment of quantum numbers was self-evident after the common final state of the and bands had been recognised.