ROTATIONAL SPECTRA, STRUCTURE, KR-83 NUCLEAR-QUADRUPOLE COUPLING-CONSTANT, AND THE DIPOLE-MOMENT OF THE KR-BENZENE DIMER

Rotational spectra were observed for the Kr-82, Kr-83, Kr-84, and Kr-86 isotopic species of the Kr-benzene dimer with the Mark II Balle-Flygare Fourier transform microwave spectrometer. The spectra are those of a symmetric top, with the Kr on the symmetry axis of the benzene. In the most abundant Kr-84 benzene dimer the rotational constants B0, D(J), and D(JK) were found to be 795.6821 (1) MHz, 1.315(1) kHz, and 7.895 (4) kHz, respectively. R, the Kr to benzene center-of-mass distance, is 3.663 angstrom and the zero-point vibrational bending of the benzene with respect to R gives an average angular displacement of 16.6-degrees. The Kr-83 quadrupole coupling constant was determined experimentally to be - 5.201(5) MHz and the dipole moment, 0. 136 (2) D. A theoretical prediction of these electrically induced properties gives results for a distributed multipole model which are superior to those using central multipoles.