Abstract
RESULTS of a quantum theory analysis of the SiN bands and of the vibrational isotope effect in these bands were given in an earlier letter to NATURE (March 22, 1924) and in a paper presented at a meeting of the American Physical Society (cf. Phys. Rev. 23, 554, 1924). It is now found that the equations given in the latter for these bands are incorrect. This is due to a wrong assignment of vibrational quantum numbers, corresponding to what may be described as an insidious violation of the combination principle. With the data first used, this violation was not apparent, but new data disclose systematic, although rather small, deviations. A new and, this time, correct assignment of quantum numbers has now been made. The following equation holds for the position of the null-lines of the Si28N bands (n = vibrational quantum number of the initial, n that of the final state of the molecule): v = 24234.2 + 1016.30n 17.77n2 + 0.41n3 0.0049n4 1145.00n + 6.570n2. The null-lines, it should be stated, can for many of the bands be measured directly on the plates At the low temperature of the active nitrogen used in generating the bands, the null-line appears as a conspicuous hole in the band structure, on the low- frequency side of the head.
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MULLIKEN, R. The Isotope Effect in the Spectrum of Silicon Nitride. Nature 116, 14 (1925). https://doi.org/10.1038/116014a0
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DOI: https://doi.org/10.1038/116014a0
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