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Volume 13: Pages 198-205, 2000
The 3d2 1G State and the 4sng Series in Neutral Calcium
Edward S. Chang 1, Rolf Engleman Jr. 2, Murray Geller 3
1Department of Physics and Astronomy, University of Massachusetts, Amtierst, Massachusetts 01003 U.S.A.
2Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131 U.S.A.
3Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 U.S.A.
We have observed and analyzed high‐resolution Fourier transform spectrometer laboratory spectra of calcium to confirm lines in the solar infrared spectra with substantial improvement in wave‐number accuracy. In Ca I, we have identified the 3d2 1G perturber level and the 4s ng series, the singlet and the triplet, for n = 5, 6, and 7. Fitting the 1G data to the Langer formula, we show that this perturber is responsible for the inversion of the 5g configuration. An Edlèn plot for the deperturbed ng and the newly discovered 6h, 7h, and 7i levels determines the dipole polarizabilityof the Ca II core to be 75.40 ± 0.05a03. The high‐ℓ levels are combined with simple theory to yield an improved ionization potential of 49305.940 ± 0.012 cm−1. We discuss conflicting reports on the 3d2 1 G level and possible implications on the 3d2 1D level, as well as other discrepant results on the core polarizability.
Keywords: calcium, energy levels, series perturbation, high‐l Rydberg states, dipole polarizability, atomic fine‐structure splittings, laboratory FTS spectra, infrared solar spectra
Received: May 15, 2000; Published online: December 15, 2008