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A Useful Approximation for Fitting Lineshapes in Photoassociation Spectroscopy of Ultracold Atoms

Published

Author(s)

Kevin Jones, Paul S. Julienne, Paul D. Lett, Eite Tiesinga

Abstract

Lineshapes in photoassociation spectroscopy of ultracold (T<1 mK) atoms are asymmetric and the peak of the line is shifted by a temperature-dependent amount from the zero-temperature threshold. In principle calculating the lineshape requires a full knowledge of both the ground and excited state potentials. We demonstrate here that an approximation based on the Wigner threshold law for scattering yields a relatively simple expression which allows one to extract line positions and linewidths directly from the data. The formula contains a few parameters (threshold frequency, linewidth, temperature, height) and does not require a detailed knowledge of the molecular potentials involved. We illustrate the utility of this approach with examples for Na photoassociation of 500 K and also discuss the limitations of the approach.
Citation
Physical Review A (Atomic, Molecular and Optical Physics)
Volume
61

Keywords

laser cooling, laser spectroscopy, lineshapes, molecular spectroscopy, photoassociation, Wigner threshold laws

Citation

Jones, K. , Julienne, P. , Lett, P. and Tiesinga, E. (1999), A Useful Approximation for Fitting Lineshapes in Photoassociation Spectroscopy of Ultracold Atoms, Physical Review A (Atomic, Molecular and Optical Physics) (Accessed October 24, 2021)
Created December 7, 1999, Updated October 12, 2021