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A Correlation of Restoring Coefficients in Molecular Potential Functions and Bond Orders Between the Different Atoms in Polyatomic Molecules

Naturevolume 166pages147148 (1950) | Download Citation



By re-investigating the Raman spectrum of C2N2 we have obtained, in addition to the frequencies already known1, four more frequencies: 521.4 cm.−1, 561.4 cm.−1, 841 cm.−1 and 2298.4 cm.−1. The last one, which appears as a weak satellite to the very strong 2328.5 cm.−1, is most probably an isotope line due to C12C13N214, and enables us to calculate the complete harmonic potential function using some infra-red frequencies also2. In order to get an interpretation of the physical nature of the potential function, it is helpful to calculate the forces called into action on different atoms i by special atomic displacements. Considering only displacements, Δx, along the axis of the linear molecule, these forces are given by

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  1. 1

    Herzberg, G., “Infrared and Raman Spectra of Polyatomic Molecules” (New York, 1946).

  2. 2

    Bailey, C. R., and Carson, S. C., J. Chem. Phys., 7, 859 (1939).

  3. 3

    Coulson, C. A., and Longuet-Higgins, Trans. Farad. Soc., 43, 88 (1947).

  4. 4

    Coulson, C. A., Trans. Roy. Soc., A, 169, 413 (1939).

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  1. Chemical Laboratory, University of Copenhagen

  2. Chemical Laboratory, Royal Veterinary and Agricultural College, Copenhagen



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