Small Carbon Clusters Doped with Vanadium Metal:  A Density Functional Study of VCn (n = 1-8)

A theoretical study of the different isomers of neutral VCn (n = 1-8) clusters has been carried out. Predictions for their electronic energies, rotational constants, dipole moments, and vibrational frequencies have been made using the B3LYP method with different basis sets. For linear and cyclic VCn clusters, the lowest-lying states correspond to quartet states, with the only exception being VC, which has a (2)Δ ground state. In the fan-type structures, the electronic ground state is found to be a quartet state for even n values, whereas for odd n values, the ground state is a doublet for VC3 and VC5 and a quartet for VC7. From the incremental binding energies, we can deduce an even-odd parity effect, with n-even clusters being more stable than n-odd ones in the linear and fan clusters. It was also found that neutral VCn clusters with n ≤ 6 prefer fan structures over linear and cyclic isomers, whereas cyclic ground states are predicted for the clusters with n > 6.