Theoretical study on the interaction of neutral and charged Ti_n (n = 1–7) clusters with one oxygen molecule

Abstract

ABSTRACT:The interactions between the neutral and charged (À2, À1, þ1, and þ2) Ti n (n ¼ 1-7) clusters and one O 2 molecule were investigated by density functional theory. The calculated results show that the oxygen molecule is dissociative on the neutral Ti n clusters. Geometrically, the two O atoms are distributed at the two sides across the neutral Ti n cluster for n ¼ 1-4 and the oxygen atom favors the three-fold hollow site for n ¼ 5, 6, and 7. The binding energy per atom (E b ) and energy gap (E gap ) show higher stability and lower chemical activity of the neutral Ti n O 2 (n ¼ 1-7) systems compared with the corresponding Ti n clusters. The adsorption energies (E ad ) exhibit a continuously ascending tendency except for n ¼ 4. The results of the addition of different charges (À2, À1, þ1, and þ2) on the most stable neutral Ti n O 2 (n ¼ 1-7) systems indicate that their geometries are usually perturbed. The stabilities of the neutral Ti n O 2 systems are enhanced by adding one negative charge. The strongest interaction of the charged Ti n clusters (À2, À1, þ1, and þ2) with O 2 molecule is found at charge þ2.

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