BHx+ (x=1-6) clusters: In the quest for superalkali cation with B-core and H-ligands

摘要

In the quest for non-metallic superalkali cation without an electronegative core, we investigate BHx+ clusters (x = 1-6) using MP2/6-311 + + G(d,p) calculations. We noticed that these BHx+ cations are stable against dissociation into BHx-1 + H+ and BHx-2++ H-2 fragments. The vertical electron affinity (EA(v)) values suggest that BH6+ cluster indeed behaves as a superalkali cation with EA(v) of 2.94 eV, lower than the IE of Cs atom. The atomic charges reveal that B contains negative charge due to electron transfer from H-ligands. The kinetic stability of BH6+ is confirmed by ab initio molecular dynamics simulations with 1 ps trajectory at various temperatures. We have also demonstrated that BH6+ superalkali cation can, in principle, be synthesized by using double protonation of BH4- superhalogen anion. Nevertheless, we have also studied AlH6+ and GaH6+ cations, whose EA(v) values are larger than that of BH6+ but smaller than the IE of the Li atom.