Iodine and chlorine nuclear quadrupole coupling in the rotational spectre of Ar center dot center dot center dot ICl and ICl: intramolecular charge transfer induced in ICl by Ar

Accurate values of the ground-state spectroscopic constants B-0, D-J, chi(a a)(I), chi(aa)(Cl) and M-bb(I) were determined for the two isotopomers Ar . .. (ICl)-Cl-35 and Ar ... (ICl)-Cl-37 of a linear complex of argon and iodi ne monochloride from analyses of their rotational spectra. Interpretation o f the changes in the nuclear quadrupole coupling constants chi(aa)(I) and c hi(aa)(Cl) of Ar ... ICl from those chi(0)(I) and chi(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 x 10(-3) e from I to Cl. The intermolecular distance r(Ar ... I) and stretching for ce constant k(sigma) were determined to be 3.576 Angstrom and 3.20 N m(-1), respectively. (C) 1999 Elsevier Science B.V. All rights reserved.