Hostname: page-component-8448b6f56d-jr42d Total loading time: 0 Render date: 2024-04-19T21:04:43.945Z Has data issue: false hasContentIssue false
  • English
  • Français

Determination of Interatomic Potentials

Published online by Cambridge University Press:  25 April 2016

R. J. Dyne
R. J. Dyne*
Affiliation:
Department of Physics, University of Queensland
Get access Rights & Permissions [Opens in a new window]

Extract

In the atmosphere of the Sun, most spectral lines are broadened by collisions between the radiating atom and neutral particles. The interaction between two atoms is usually represented by the multipole expansion of the total interaction potential. For two neutral atoms, the first non-zero term in this expansion arises from induced dipole-induced dipole forces and is proportional to r-6. Most calculations of broadening due to neutral atoms have assumed this van der Waals interaction, V(r) = —C6 r-6, between the atoms. Such an assumption is only valid if the interatomic separation is much greater than the sum of the radii of the two atoms so that no overlap occurs and only the leading term of the multipole expansion need be considered. However, in fitting the wings of solar line profiles, O’Mara found that the value of the van der Waals constant, C6, had to be increased by up to a factor of ten in order to obtain agreement between theoretical and observed profiles.

Type
Contributions
Information
Publications of the Astronomical Society of Australia , Volume 2 , Issue 1 , July 1971 , pp. 38 - 40
Copyright
Copyright © Astronomical Society of Australia 1971

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1 O’Mara, B. J., Ph.D. thesis. University of California, Los Angeles (1967) (unpublished).Google Scholar
2 Heitler, W. and London, F., Z. Phys. 44, 455 (1927).Google Scholar
3 Unsöld, A., ‘Physik der Sternatmosphören’, Springer-Verlag, Berlin 1955, p. 332.Google Scholar
4 Smith, G., Proc. Roy. Soc, A297, 288 (1967).Google Scholar
5 Vaughan, J. M. and Smith, G., Phys. Rev., 166, 17 (1968).Google Scholar
6 Hindmarsh, W. R., Petford, A. D. and Smith, G., Proc. Roy. Soc, A297, 296 (1967).Google Scholar
7 Hindmarsh, W. R., du Plessis, A. N. and Farr, Judith M., J. Phys. B.: Atom. Molec. Phys., 3, L5 (1970).Google Scholar
8 Baranger, M., ‘Atomic and Molecular Physics’, (ed. D. Bates), Academic Press, New York 1962, Chap. 13.Google Scholar
9 Lewis, E. L., McNamara, L. F. and Michels, H. H., to be published Phys. Rev. A.Google Scholar