Polynomial coefficients for calculating O₂ Schumann‐Runge cross sections at 0.5 cm⁻¹ resolution

Abstract

We have fitted O 2 cross sections from 49,000 to 57,000 cm −1 with temperature dependent polynomial expressions, providing an accurate and efficient means of determining Schumann‐Runge band cross sections for temperatures 130<T<500 K. The least squares fits were carried out on a 0.5 cm −1 spectral grid, using cross sections obtained from a Schumann‐Runge line‐by‐line model that incorporates the most recent spectroscopic data. The O 2 cross sections do not include the underlying Herzberg continuum, but they do contain contributions from the temperature dependent Schumann‐Runge continuum. The cross sections are suitable for use in ultraviolet transmission calculations at high spectral resolution. They should also prove useful for updating existing parameterizations of ultraviolet transmission and O 2 photolysis.