Laser fluorescence state selected and detected molecular beam magnetic resonance in I2

Abstract

A molecular beam magnetic resonance experiment, using laser fluorescence for state selection and beam detection, has been performed on I₂. Twenty ΔF=±1 hyperfine transitions were observed in the v=0, J=13 level of the ground electronic state. The transitions had a FWHM linewidth of 5–15 kHz in the 100–400 MHz region and were observed in zero external field. eqQ, spin rotation, tensor spin–spin, and scalar spin–spin interactions of −2 452 583.7(16), 3.162(8), 1.58(5), and 3.66(3) kHz, respectively, were obtained. Using these X ¹Σ state constants, the precise optical data of Hackel, Casleton, Kukolich, and Ezekiel [Phys. Rev. Lett. 35, 568 (1975)] were reanalyzed to obtained hyperfine properties of the v=43, J=12 B ³Π₀ electronic state. In the same order as above, these constants are −558 669(8), 190.13(12), −100.2(7), and 0.2(4) kHz. These values for both the X and B states differ significantly from those previously reported. Neither magnetic octupole nor electric hexadecupole interactions were required, however, upper limits for these interactions are established for both electronic states.