Methods for the calculation of spectral absorption coefficients for combined Doppler and Lorentz broadening are summarized. The “curves of growth” have been extended to cover the ranges of parameters which arise in spectroscopic studies on flames.
S. S. PENNER and R. W. KAVANAGH, "Radiation from Isolated Spectral Lines with Combined Doppler and Lorentz Broadening," J. Opt. Soc. Am. 43, 385-388 (1953)