Photodissociation of S(2) (X(3)Σ(g)(–), a(1)Δ(g), and b(1)Σ(g)(+)) in the 320–205 nm Region

[Image: see text] Photodissociation of vibrationally and electronically excited sulfur dimer molecules (S(2)) has been studied in a combined experimental and computational quantum chemistry study in order to characterize bound-continuum transitions. Ab initio quantum chemistry calculations are carried out to predict the potential energy curves, spin–orbit coupling, transition moments, and bound-continuum spectra of S(2) for comparison with the experimental data. The experiment uses velocity map imaging to measure S-atom production following S(2) photoexcitation in the ultraviolet region (320–205 nm). A pulsed electric discharge in H(2)S produces ground-state S(2) X(3)Σ(g)(–)(v = 0–15) as well as electronically excited singlet sulfur and b(1)Σ(g)(+)(v = 0, 1), and evidence is presented for the production and photodissociation of S(2) a(1)Δ(g). In a previous paper, we reported threshold photodissociation of S(2)X(3)Σ(g)(–)(v = 0) in the 282–266 nm region. In the present study, S((3)P(J)) fine structure branching and angular distributions for photodissociation of S(2) (X(3)Σ(g)(–)(v = 0), a(1)Δ(g) and b(1)Σ(g)(+)) via the B″(3)Π(u), B(3)Σ(u)(–) and 1(1)Π(u) excited states are reported. In addition, photodissociation of the X(3)Σ(g)(–)(v = 0) state of S(2) to the second dissociation limit producing S((3)P(2)) + S((1)D) is characterized. The present results on S(2) photodynamics are compared to those of the well-studied electronically isovalent O(2) molecule.