Transition Probabilities of Forbidden Lines

Author: Pasternack, Simon

Year: 1939

Degree: Dissertation (Ph.D.)

Advisor: Houston, William Vermillion

Committee Member: Unknown, Unknown

Option: Physics

DOI: 10.7907/056j-b434

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 np4 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 pk configurations; in particular, a non-zero value is found for the probability of the 3PO - '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 pk 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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