Structural rearrangement in gas phase niobium carbide clusters, NbnC3 and NbnC6

Abstract

Niobium carbide clusters were formed in the gas phase by mixing vapors of niobium and carbon. When a carbon trimer, C3, was richly formed in the vapor, clusters with compositions NbnC3k+ (n=2–10, k=0–4) were abundantly observed after photoionization at 215nm, enabling the presumption that a C3 unit could be a building block of the observed clusters. Contrary to this presumption, photoionization efficiency spectra in 215–286nm suggest that the clusters should be assigned to atomically mixed niobium carbide. Structural rearrangement of the clusters into the atomically mixed form is consistent with the results of DFT calculations.