Mass Spectrometry and Theoretical Investigation of VN n+ ( n = 8, 9, and 10) Clusters.

VN n+ clusters were generated by laser ablation and analyzed by mass spectrometry. The results showed that VN8+, VN9+, and VN10+ clusters were formed, and the mass peak of VN8+ is dominant in the spectrum. The VN8+ cluster was further investigated by a photodissociation experiment with 266 nm photons. Density functional theory calculations were conducted at the M06-2X/6-311+G(d,p) level to search for stable structures of VN n+ ( n = 8, 9, and 10) and their neutral counterparts. The theoretical calculations revealed that the most stable structure of VN8+ is in the form of V(N2)4+ with D 4h symmetry. The binding energy from the calculation is in good agreement with that obtained from the photodissociation experiments. The global minimum structures of VN8, VN9+/0, and VN10+/0 contain a similar substructure of the N4 ring and exhibit energy properties. The most stable structure of VN9+ is in the form of (η2-N4)V+N(N2)2 with C1 symmetry, while that of VN10+ is in the form of (η4-N4)V+(N2)3 with C s symmetry. For neutral VN8, VN9, and VN10, (η4-N4)V(N2)2, (η4-N4)V(N3)(N2), and (η4-N4)V(N2)3 are their ground-state structures, with decomposition into one V atom, and corresponding quantities of N2 can release energies of about 50.20, 96.28, and 57.76 kcal/mol, respectively.