In the case of a band model concept for molecular line absorption, since the absorption coefficient is a rapidly varying function of frequency, the averaged transmittance does not, in general, obey the simple exponential law with range. Mathematical expressions are obtained for the molecular line absorbers in the Lowtran 3B computer code. These expressions exhibit a variation of transmission, which is exponential with the range raised to some power the value of which is dependent on the contributor.
© 1978 Optical Society of America
Ronald R. Gruenzel, "Mathematical expressions for molecular absorption in Lowtran 3B," Appl. Opt. 17, 2591-2593 (1978)