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Solvent effects in dense gases
Author(s) -
McGlynn S. P.,
Asaf U.,
Kumar D.,
Felps S.,
Rupnik K.,
Klasinc L.
Publication year - 1991
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560390316
Subject(s) - polarizability , scattering , chemistry , atomic physics , bohr model , scattering length , range (aeronautics) , spectral line , absorption (acoustics) , molecular physics , physics , optics , quantum mechanics , materials science , molecule , organic chemistry , composite material
The effects of perturber gases, partial pressures in the range 0–50 atm, on the absorption spectra of high‐ n Rydbergs, n ≥ 10, in methyl iodide and benzene have been investigated. The perturbers were rare gases and H 2 . It has been shown that the spectroscopic energy shift Δ = Δ(ρ, n ) is given by Δ = Δ°ρ, where ρ is the number density of the perturber, for n ≥ 10. The shift data can be interpreted using a Fermi model, and values of scattering lengths for perturbers can be extracted. These scattering lengths are internally consistent, independent of the absorber, and in excellent agreement with electron‐swarm results. Given that the Fermi model is nonspecific and microscopic, scattering shifts and lengths for mixtures of perturber gases can be predicted. These predictions, having been verified by experiment for He/Ar mixtures, provide a means of “tailoring” any required scattering length. Finally, it is shown empirically that the determinative scattering parameter is the polarizability of the perturber, and a universal relationship a = −0.26α + 1.18 between scattering length a , in Bohr radii, and polarizability α is found to exist.