Accurate calculation of electron affinity for S3

The accurate equilibrium structures of S-3 and S(3)(-)are determined by the coupled-cluster method with single, double excitation and perturbative triple excitation (CCSD(T)) with basis sets of aug-cc-pV(n+d)Z (n = T, Q, 5, or 6), complete basis set extrapolation functions with two-parameters and three-parameters, together with considering the contributions due to the core-valence electron correlation, scalar relativistic effects, spin-orbit coupling, and zero-point vibrational corrections. Our calculations show that both the neutral S-3 and anion S-3(-) have open forms with C-2v, symmetry. On the basis of the stable geometries, the adiabatic electron affinity of S-3 is determined to be 19041(11) cm(-1), which is in excellent agreement with the experimental data (19059(7) cm(-1)). The dependence of geometries and electron affinity on the computation level and physical corrections is discussed. The present computational results are helpful to the experimental molecular spectroscopy and bonding of S-3.