Transition Probabilities of Forbidden Lines

Citation

Pasternack, Simon (1939) Transition Probabilities of Forbidden Lines. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/056j-b434. https://resolver.caltech.edu/CaltechTHESIS:12132024-233828788

Abstract

Recent work on forbidden lines has made it desirable to re-examine and extend the calculations made by Condon on the theoretical transition probabilities of these lines for a few atoms in the np², np³ and np^{4 configurations.}

The method developed by Condon for the computation of these transition probabilities is described and discussed. A few modifications are introduced, such as the use of recently developed formulae for magnetic dipole line strengths in LS coupling and the use of second-order approximations to the wave functions in special cases. The evaluation of the parameters involved in the breakdown of LS coupling is also carried out in a somewhat different manner.

Formulae are derived for the magnetic dipole and electric quadrupole contributions to the transition probabilities for the p², p³, p⁴ and d² configurations. A few errors are found in Condon's calculations for the p^k configurations; in particular, a non-zero value is found for the probability of the ³P_O - ^'D₂ transition in the p² configuration. This line was recently observed in 0 III.

Numerical computations are made of the transition probabilities of fifty-one atoms in the p^k configurations. The formulae for the d² configuration are applied to the single case of Fe VII. The difficulties which arise in these calculations are discussed with regard to their implications about the general validity of the method.

A short discussion is given of an application of the calculations to a question concerning the permitted lines of 0 III present in nebular spectra.

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