Tunable synchrotron radiation has been used to probe the dissociation dynamics of thietane (C3H6S) at 193 nm, providing selective determination of the translational energy distribution of both excited (D-1) and ground-state (P-3) sulfur atoms, with momentum-matching to the C3H6 co-fragment. The results suggest that the sulfur atom is produced almost exclusively in its excited (D-1) state, with ground-state (P-3) production less than 5%. The first single-photon ionization efficiency (PIE) spectrum for the S(D-1) state with a resolution of 0.2 eV is reported. (C) 2002 Elsevier Science B.V. All rights reserved.