Potassium iodide cluster based superhalogens and superalkalis: Theoretical calculations and experimental confirmation

Abstract

The (KI)nI− and (KI)nK+ (n = 1–3) clusters were studied by quantum chemical calculations. The calculated vertical detachment energies (VDEs) of (KI)nI− are higher than those of halogen anions, thus can be classified as superhalogen anions; while the calculated vertical electron affinities (VEAs) of (KI)nK+ are lower than those of alkali metal cations, thus can be recognized as superalkali cations. The calculated VEA for (KI)K+, i.e., K2I+, agrees well with previous measurement, and the calculated VDEs for (KI)nI− were confirmed by negative ion photoelectron (NIPE) spectroscopy. Furthermore, supersalts could be formed by those superhalogens and superalkalis, and K3I3 is an example formed by K2I+ and KI2− subunits.