Speed-dependent spectral line profile including line narrowing and mixing

A line profile model was developed that accounts for all essential underlying physical mechanisms. The model is based on the quantum-mechanical collision integral kernel calculated for intermolecular interaction potentials proportional to r(-n) with n=3...6 where r is the distance between colliding molecules. It was shown that collisions of molecules with scattering on classical small angles flatten the line profile. The relative flattening reaches 10% for n=3 and has a smaller value, similar to 2%, for n=6 in conditions of inhomogeneous line broadening. An algebraic expression for the line profile was obtained, which allows processing recorded spectra with preliminary estimation and constraint of some of the profile's parameters. (C) 2016 Elsevier Ltd. All rights reserved.