Modeling of IR absorption spectra of the mixture CO_2-He at moderate and high pressures

摘要

The He-broadened spectra of carbon dioxide are calculated within the pressure range 2-800 arm in the absorption regions of the bands v_2, v_3, and 3v_3 that are positioned from 590 to 7020 cm~(-1). The main difficulty is consideration of the line shape narrowing at relatively high pressures. For Q-branches, this effect is observed at atmospheric conditions and, therefore, it is important for remote sounding of the gas atmosphere. The mixtures of the mentioned gases are well studied in experiments and it can serve as a good test for validating the simulating techniques developing. The line by line method is used with modeling of the single line shape without the conventional interference of lines. The problem is focused on the order and disorder in arrangement of the rotational lines within P-, R-, and Q-branches of vibrational bands. A database CDSD-1000 in the HITRAN format is reformatted with adding supplement four parameters for every entry. The physical meaning of the phenomena known as the line and branch mixing is discussed.