Super-Accuracy Calculation for the Half Width of a Voigt Profile

A simple approximation scheme to describe the half width of the Voigt profile as a function of the relative contributions of Gaussian and Lorentzian broadening is presented. The proposed approximation scheme is highly accurate and provides an accuracy better than 10(-17) for arbitrary alpha(L)/alpha(G) ratios. In particular, the accuracy reaches an astonishing 10(-)(34) (quadruple precision) in the domain 0 <= alpha(L)/alpha(G) <= 0.2371 ? alpha(L)/alpha(G) >= 33.8786.

Automated summary

This paper presents a simple approximation scheme to describe the half width of the Voigt profile as a function of the relative contributions of Gaussian and Lorentzian broadening. The proposed scheme is highly accurate and provides accuracy better than 10(-17) for arbitrary alpha(L)/alpha(G) ratios.