LAUSR

Classical Molecular Dynamics Simulations (CMDS) are used for calculations of the Collision Induced Absorption (CIA) by pure N2 in the (2.1-2.2 µm) region of the first overtone band. They lead to reasonable (±15%) agreement with the only two laboratory measurements available, at 97 K and room temperature. Based on these experiment/theory comparisons, empirical corrections are made to the CMDS-calculated CIA of pure N2 in the 200-300 K temperature range. In addition, the contribution of N2-O2 collisions is, in the absence of any laboratory measurement, calculated and a simple semi-empirical model (the first of its kind) is built in order to predict the CIA of N2 under Earth atmosphere conditions. This is successfully validated by comparisons with ground based atmospheric transmission spectra in the 2.1-2.2 µm region.