Theoretical investigation of geometry and stability of small lithium-iodide Li_<i>n</i>I (<i>n</i>= 2-6) clusters

Abstract

We present theoretical investigation of the structural characteristics and stabilities of neutral and positively charged LinI (n = 2-6) species. The structural isomers were found by using a randomized algorithm to search for minima structures, followed by B3LYP optimizations; the single-point RCCSD(T)/cc-pwCVTZ(-PP) calculations were performed in order to compute relative energies, binding energies per atom, adiabatic and vertical ionization energies, and dissociation energies. Stability was compared to the pure lithium clusters; there is a typical odd-even alternation; iodine doped clusters are more stable than pure lithium clusters. Lithium “cage” transfers its valence electron to the iodine atom to form neutral and cationic clusters. An electron departures the lithium cage upon ionization. An important reason for the larger stability of closed-shell species is the existence of the HOMO 3c/2e natural bond orbitals. © 2013 Wiley Periodicals, Inc.