Iodine and chlorine nuclear quadrupole coupling in the rotational spectra of Ar⋯ICl and ICl: intramolecular charge transfer induced in ICl by Ar

Abstract

Accurate values of the ground-state spectroscopic constants B 0, D J , χ aa (I), χ aa (Cl) and M bb (I) were determined for the two isotopomers Ar⋯I 35 Cl and Ar⋯I 37 Cl of a linear complex of argon and iodine monochloride from analyses of their rotational spectra. Interpretation of the changes in the nuclear quadrupole coupling constants χ aa (I) and χ aa (Cl) of Ar⋯ICl from those χ 0(I) and χ 0(Cl), respectively, of the free molecule shows that the electric charge redistribution within ICl when Ar⋯ICl is formed is equivalent to the transfer of 5.4×10 −3 e from I to Cl. The intermolecular distance r(Ar⋯I) and stretching force constant k σ were determined to be 3.576 Å and 3.20 N m −1, respectively.