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New Experimental and Theoretical Results for Argon Broadening and Shift of HCO + Rotational Lines
Author(s) -
Buffa Giovanni,
Dore Luca,
Tinti Francesca,
Meuwly Markus
Publication year - 2006
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200600166
Subject(s) - semiclassical physics , argon , atomic physics , chemistry , coupling (piping) , ion , sign (mathematics) , potential energy surface , molecular physics , physics , ab initio , materials science , quantum mechanics , mathematical analysis , mathematics , organic chemistry , metallurgy , quantum
An experimental and theoretical study of the pressure broadening and the pressure shift of three HCO + rotational lines (j=4←3, 5←4 and 6←5) perturbed by collisions with Ar is presented. The measurements are carried out at 77 K and are compared to close‐coupling calculations performed on an accurate potential energy surface for the Ar–HCO + interaction extending from small to very large separations between the ion and the perturber. For the pressure broadening, agreement between experiment and theory is satisfactory for both close‐coupling and semiclassical calculations. For the pressure shift, however, close‐coupling calculations are superior. The results agree with experiment in sign and order of magnitude, while semiclassical calculations are inaccurate for the shift of the presently studied lines because they neglect the contribution of strong collisions.