Temperature dependence of line mixing effects in the stimulated Raman Q-branch of CO in He: A further test of close coupling calculations

The isotropic Raman Q-branch of CO was analyzed using Raman loss spectroscopy for mixtures with helium (He) at low temperatures. To provide full homogenization, the gas mixtures were prepared in steel cylinders at least 24 hours before the examination. 1% CO was mixed with He at a total pressure of 9 bar. It was found that the CC formalism is an efficient tool for a priori prediction of line coupling effects for a wide variety of CO-He spectra and it also predicts the isotropic Q-branch spectra at a low temperature.