An Atomic Beam Method for Measuring Absolute f-Values

Citation

Davis, Milford Hall (1955) An Atomic Beam Method for Measuring Absolute f-Values. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/DK7Y-YR63. https://resolver.caltech.edu/CaltechETD:etd-12102003-104042

Abstract

Very few absolute oscillator strengths (f-values) are known for lines in complex spectra; little confidence can be placed in most of the results which have been reported. In an effort to remedy this situation an atomic beam apparatus was constructed and used for the experimental determination of the absolute f-values of resonance lines in the Fe I, CR I, Mn I, and Cu I spectra. The theory of the formation of absorption lines when light from a source of continuous radiation passes through an atomic beam was developed and is presented in some detail. The atomic beam apparatus, devices for temperature measurement and control, and methods for determining the density of atoms in the atomic beam are described. A discrepancy was noticed between the predicted and observed variation of the total absorption for a particular line with the number of absorbing atoms. The observed relation was used as an auxiliary means for the determination of absolute f-values in a manner which is described at length. Since the resulting f-values differ somewhat from those calculated from the data on the basis of the atomic beam theory, both sets of results are reported. Recommendations are made for further research to resolve this problem.

Thesis Files