The fluorosulfate radical: Rotational analysis of the 5160 Å system and molecular geometry

Abstract

Empirical analysis of the rotational structure of the origin band of the 5160 Å absorption transition of the fluorosulfate radical shows that it can be treated as two separate vibronic transitions to Jahn-Teller/spin orbit split potential surfaces of an 2 E excited electronic state. The transition ( +0 0 0) to the upper surface appears to consist of a series of prominent P Q sub-bands with underlying R Q sub-bands, and series of prominent P P K ( J) lines. Similar structure is observed for other bands in the system. For the molecule in the v 1 = v 2 = ⋯ = 0 level associated with the upper potential surface in the excited state, the derived rotational constants are A 0′ = 0.172 0cm −1, and B 0′ = 0.157 9cm −1; the latter is almost identical with the value of B 0″ in the ground state. The electronic orbital angular momentum is partially quenched in this upper state level by the C 3 v potential symmetry of the molecule, the electronic Coriolis coefficient ζ e being about 0.45. The proposed excited state geometry, on the assumption of C 3 v symmetry is; r (SO) = 1.49 A ̊ , r (SF) = 1.64 A ̊ , angle OSF = 106°.