Dipole moment of ArH+X1Σ+ from analysis of pure rotational and vibration-rotational spectra

By a direct fit to 431 experimental wave numbers of pure rotational and vibration-rotational transitions of ArH(+)X(1)Sigma (+) in six isotopic variants, 16 coefficients of radial functions defining the Born-Oppenheimer potential energy, adiabatic and nonadiabatic effects have been determined at sigma = 0.885 and F = 4.07 x 10(15). Using a relation between nonadiabatic rotational effects and electric and magnetic properties of the molecule, a permanent dipole moment of (ArH+)-Ar-40-H-1 is estitnated as mu (0) = 2.12(55) D which agrees both with the ab initio value 2.2(1)D and the experimental result mu (0) = 3.0(6) D within quoted error limits. (C) 2001 Elsevier Science B.V. All rights reserved.