Padé Summation of the Cauchy Dispersion Equation*
- 1 July 1969
- journal article
- Published by Optica Publishing Group in Journal of the Optical Society of America
- Vol. 59 (7), 863-871
- https://doi.org/10.1364/josa.59.000863
Abstract
A method is presented, based on recognition of the Cauchy dispersion equation as a series of Stieltjes, for the bounded extrapolation of long-wavelength refractivity data into the far ultraviolet. The extrapolation is performed with the [n, n−1] and [n,n] Padé approximants, which improve the convergence of the Cauchy equation and provide upper and lower bounds to its exact sum. Illustrative applications are given for atomic hydrogen, the inert gases, and molecular hydrogen, oxygen, and nitrogen. Comparison with the exact dispersion curve for atomic hydrogen and with available theoretical and experimental ultraviolet-dispersion data for the inert and diatomic gases indicates that the Padé approximants converge rapidly to accurate refractivity values. In addition, recognition of the Cauchy equation as a series of Stieltjes provides nontrivial constraints on the Cauchy coefficients; these afford a test of their accuracy and allow estimates of higher-order coefficients from measured refractivity data.Keywords
This publication has 11 references indexed in Scilit:
- Dynamic Polarizability of HeliumPhysical Review B, 1968
- Padé Approximants and Bounds to Series of StieltjesJournal of Mathematical Physics, 1968
- Information content of the born seriesJournal of Computational Physics, 1966
- Index of Refraction and Sum Rules for HeliumPhysical Review B, 1965
- Long-range interaction forces between inert gas atomsPhysics Letters, 1964
- Refractive Index of the Hydrogen MoleculeThe Journal of Chemical Physics, 1964
- A Variation-Perturbation Approach to the Interaction of Radiation with Atoms and MoleculesThe Journal of Chemical Physics, 1963
- Determination of the Refractive Indices of Gases in the Vacuum Ultraviolet I The ?erenkov Radiation MethodJournal of the Optical Society of America, 1963
- The refractive indices and Verdet constants of the inert gasesProceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, 1960
- The refraction and dispersion of neon and heliumProceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character, 1932