Equilibrium structure and potential function of selenium dioxide by microwave spectroscopy

Abstract

Microwave spectra of the SeO 2 molecule have been observed between 8000 and 36,000 MHz in the ground state and in the first excited states of all the normal vibrations. The equilibrium structural parameters are determined to be r e = 1.607 6 ± 0.0006 A ̊ and θ e = 113°50′, common for both 80SeO 2 and 78SeO 2 isotopic species. The frequency of ν 2 and the Coriolis coupling constant are obtained from the inertia defects in the excited vibrational states. The quadratic force constants are calculated from these values combining with the infrared frequencies of ν 1 and ν 3 and the centrifugal distortion constants. The cubic potential constants are determined from the vibration-rotation interaction constants α.