MICROWAVE-SPECTRUM, STRUCTURE, AND NUCLEAR-QUADRUPOLE COUPLING-CONSTANT TENSOR OF VINYL BROMIDE AND IODIDE

Microwave spectra of vinyl bromide and its 15 isotopic species and of vinyl iodide and its six isotopic species have been measured. A least-squares analysis of the observed frequencies gave rotational, quartic centrifugal distortion constants and the components of the nuclear quadrupole coupling constant tensor for all the isotopic species. The rs structures have been established from the moments of inertia calculated from the observed rotational constants. The observed nuclear quadrupole coupling constant tensor in the inertial principal axes system could be transformed into that in its own principal axes system. The molecular structures and nuclear quadrupole coupling constant tensors of vinyl halides were compared with each other and with those of ethyl halides. © 1990.