Theoretical Study of MgCn, MgCn+, MgCn- (n = 1−7) Open-Chain Clusters

Abstract

MgC n (n = 1-7) open-chain clusters, as well as their cationic and anionic derivatives, have been studied by means of the B3LYP density functional method. Results for several molecular properties which could help in theirpossible experimental characterization, such as equilibrium geometries, electronic energies, dipole moments and vibrational frequencies, are provided. MgC n clusters are predicted to be linear with triplet ground states, with the only exception of MgC 2 that has a 1 Σ ground state. Both cationic and anionic clusters have doublet ground states, except for the first members of the series, MgC + and MgC - , which are found to have 4 Σ ground states. The analysis of incremental binding energies shows that both MgC n and MgC n - species exhibit a clear even-odd alternation in stability, n-even clusters being always more stable than n-odd ones. This alternation is also reflected in the electron affinity values, which are higher for n-even clusters. In the case of the cationic clusters, the stability alternation is reversed along the series, and for larger MgC n + species n-odd species seem to be more stable.