The photoionization thresholds of polymers of hydrogen sulfide (H2S)nwere measured forn= 1ndash;7. They are, for increasing values ofn, 10.449plusmn;0.006, 9.74plusmn;0.01, 9.63plusmn;0.01, 9.61plusmn;0.01, 9.58plusmn;0.01, 9.50plusmn;0.02, and 9.63plusmn;0.03 eV, respectively. The sequence of ionization thresholds with increasingndoes not correlate well with a linear relationship to 1/nas do other nonmetal clusters reported previously. We find a binding energy for (H2S)2+of 0.737plusmn;0.012 eV. This value diminishes for each successive cluster ton= 5. Atn= 6 the incremental binding is almost as large as for trimer formation while formation ofn= 7 is endoergic, that is, (H2S)7+is unstable with respect to (H2S)6++H2S.
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