Comparative DFT study of N2 and NO adsorption on vanadium clusters V(n) (n = 2-13)

Using gradient-corrected density functional theory, we have comparatively studied the adsorption properties of diatomic molecules N(2) and NO on vanadium clusters up to 13 atoms. Spontaneous dissociation is found for N(2) adsorbing on V(n) with n = 4-6, 12, and for NO with n = 3-12, respectively, whereas for the rest of the clusters, N(2) (NO) molecularly adsorbs on the cluster for all the possible sites. The incoming N(2) retains the magnetism of V(n) except for V(2) and V(6) whose moments are quenched from 2 μ(B) to zero. Consequently, the moments of V(n)N(2) (n = 2-13) show even/odd oscillation between 0 and 1 μ(B). On the adsorption of NO, the magnetic moments of V(n) with closed electronic shell are raised to 1 μ(B) at n = 4, 8, and 10, and 3 μ(B) at n = 12, whereas for open shell clusters, their magnetic moments increase for n = 5 and 9 and decrease for n = 2, 3, 5-7, 11, and 13 by 1 μ(B). These findings are rationalized by combinatory analysis from several aspects, for example, the geometry and stability of bare clusters, charge transfer induced by the adsorption, feature of frontier orbitals, and spin density distribution.