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Rotational Spectrum of the Mixed van der Waals Triad Pyridine–Ar–Ne
Author(s) -
Melandri Sonia,
Giuliano Barbara M.,
Maris Assimo,
Evangelisti Luca,
Velino Biagio,
Caminati Walther
Publication year - 2009
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.200900366
Subject(s) - isotopologue , chemistry , van der waals force , pyridine , quadrupole , rotational spectroscopy , ab initio , conformational isomerism , ab initio quantum chemistry methods , van der waals radius , kinetic isotope effect , atomic physics , deuterium , molecule , physics , medicinal chemistry , organic chemistry
We report the Fourier transform microwave spectra of four isotopologues of the hetero triad pyridine–Ar–Ne, formed by the combination of two isotopes of the nitrogen atom ( 14 N and 15 N) in pyridine with two isotopes of the rare gas (RG) atoms ( 20 Ne and 22 Ne), by using pulsed jet spectroscopy. We detected the conformer denoted [1,1], with the Ne and Ar atoms located one on each side of the ring plane. The [2,0] species, with the two RG atoms on the same side of the ring, was not observed. Ab initio MP2/6‐311++G** calculations suggest the rotational spectrum of this species to be complicated by the presence of several almost equivalent minima, separated by very low barriers. Four structural van der Waals parameters, R Ar , R Ne , θ Ar and θ Ne , which localize the RG atoms with respect to pyridine, are determined. The 14 N nuclear quadrupole coupling constants are obtained for the isotopologues containing this nucleus.