H2O−N2 collision-induced absorption band intensity in the region of the N2 fundamental: ab initio investigation of its temperature dependence and comparison with laboratory data

The present paper aims at ab initio and laboratory evaluation of the N2 collision-induced absorption band intensity arising from interactions between N2 and H2O molecules at wavelengths of around 4m. Quantum chemical calculations were performed in the space of five intermolecular coordinates and varying NN bond length using MllerPlesset perturbation and CCSD(T) methods with extrapolation of the electronic energy to the complete basis set. This made it possible to construct the intermolecular potential energy surface and to define the surface of the NN dipole derivative with respect to internal coordinate. The intensity of the nitrogen fundamental was then calculated as a function of temperature using classical integration. Experimental spectra were recorded with a BOMEM DA3-002 FTIR spectrometer and 2m base-length multipass White cell. Measurements were conducted at temperatures of 326, 339, 352 and 363K. The retrieved waternitrogen continuum significantly deviates from the MTCKD model because the relativ...