Photodetachment-photoelectron spectroscopy of disulfanide: the ground and first excited electronic state of HS2 and DS2

Photodetachment-photoelectron spectra of HS2- and DS2- are presented, The obtained electron affinities (EA (HS2) = 1.916 +/- 0.015 eV and EA (DS2) = 1.918 +/- 0.015 eV) are in good agreement with earlier results (S. Moran and G.B. Ellison. J. Phys. Chem., 1988, 92, 1794). Photodetachment into the neutral ground state of the radicals HS2 and DS2 leads to excitation of the S-S stretching mode, whereas photodetachment into the first excited state causes a S-S-H bending and a weak S-H stretching motion. Additionally, weak peaks of S-2 were observed in the spectra of HS2 and DS2, leading to the conclusion that photodetachment with 2.77 eV (448 nm) causes dissociation of HS2 and DS2 into S-2 and H/D. Taking 2.77 eV as an upper limit for D-0(S-2-H) a lower limit for Delta fH(0)(HS2(g)) of 100.8 kJ mol(-1) is obtained which is an improvement on the literature value of 107.145 +/- 10.46 kJ mol(-1).