MOLECULAR BEAM LINESHAPE ANALYSIS
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Date
1990
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
In earlier work1-2 we have described a statistical technique for locating the centers of spectral lines obtained with a molecular beam spectrometer. That technique is of value for isolated lines because it does not require knowledge of a specific lineshape. We were reluctant to try fitting a specific lineshape function for two main reasons: 1. Velocity averaging produces subtle effects on the lineshape that are difficult to account for because detailed velocity distributions are not known, and 2. One of the experimental parameters, namely the amplitude of the radio frequency field, is difficult to measure, and may vary significantly over the length of the transition region. With LiF the hyperfine coupling constants are small enough that, even with our 200 Hz linewidth, most of the lines overlap. We therefore had an incentive to pursue the possibility of fitting the specific lineshape in order to deconvolute the overlapping lines. We have found that the effects of velocity averaging can be accommodated in a very simple way by using a two-point velocity distribution, while the rf amplitude can be treated as a variable determined by the fitting process. The result is an excellent fit of the Rabi lineshape to our experimental data which not only provides center frequencies, but also gives us meaningful values for other experimental parameters including the rf amplitude.
Description
$^{\ast}$ Work supported by NSF grant PHY-8617538 $^{1}$ J. Cederberg. et al, Symposium on Molecular Spectroscopy, Ohio State University, 1985. $^{2}$ J. Cederberg, et al, J. Mol. Spect. 122, 171-181 (1987).
Author Institution: Physics Department, St. Olaf College
Author Institution: Physics Department, St. Olaf College