Microwave Spectrum of the SO Radical. Equilibrium S-O Distance, Electric Quadrupole Coupling Constant and Magnetic Hyperfine Structure Constants

The molecular constants in the first excited vibrational state of the 32 SO radical are obtained as well as in the ground state. The equilibrium constants are much improved; B e =21609.5 5 ±0.15Mc/sec, λ e =157780±25 Mc/sec, and r e =1.48108±0.00005Å. Spectra of other two isotopic species, 34 SO and 33 SO, are also analyzed. Hyperfine interaction due to the 33 S nucleus is studied in detail, and \({}∑ᵢ(3cos²χᵢ-1)/{2rᵢ}³{}{=}-3.4{×}10²⁴\)cm -3 , \({}∑ᵢ\{(3cos²χᵢ-1)/{2rᵢ}³\}{·}siz{}_{Sz{=}1}{=}-5.32{×}10²⁴\)cm -3 , \({}∑ᵢδ( rᵢ)siz{}_{Sz{=}1}{=}3.96{×}10²³\)cm -3 are obtained. The Stark effect of the 33 SO spectra is worked out in detail and utilized for the assignment of the weak lines.