Unified Impact Theory for Velocity-Changing Effects and Speed Dependencies in Neutral Species Lineshapes

[摘要] A dipole correlation function which incorporates velocity-changing (motional narrowing) effects and theeffects of speed-dependent Lorentz relaxation rates into otherwise Voigt profile correlation functions is developed,based partly upon previous work by the author. For the first time simple closed expressions, which lend themselvesto elementary calculation beginning only with the relevant parts of intermolecular interaction energies, aredeveloped for the cubic time-dependent term within the exponent describing the decay of the correlation function. This term is of first order in perturber number density, as are the Lorentz parameters, and is complex, therebyallowing for narrowing, changing in shape and asymmetry in the line profile. “Soft” and “hard” collisions play no explicit role, though both are variously present for each line. Quartic time dependencies are also discussed,though they are thought to be negligible in nonhydrogen molecular spectroscopy. Finally, some comments areadded about a relevant technique for hydrogen spectra.

[学科分类] 光谱学