Metal segregation and electronic properties of lithium suboxide clusters

The structural and electronic properties of neutral lithium suboxide clusters Li4+pO2(0 less than or equal to p less than or equal to 9) are studied by means of ab initio molecular dynamics simulations. For few excess Li atoms Li-O bonds are formed which progressively weaken as the O coordination number increases. Then Li attachment proceeds around nonstoichiometric ionic cores and results in metal segregation. The evolution of the growth mode correlates with a change of the electronic properties, some of which can be probed experimentally to obtain structural information. We predict that at small p Li4+pO2 clusters have ionization potential much lower than pure Li-p. A generalization of our results to oxidized alkali-metal surfaces and bulk suboxides is proposed.