Structural Evolution and Electronic Properties of V_nC₂^0/– and V_nC₄^0/– (n = 1–6) Clusters: Insights from Photoelectron Spectroscopy and Theoretical Calculations

Abstract

The structural evolution and electronic properties of VnC2(-/0) and VnC4(-/0) (n = 1-6) clusters were investigated using photoelectron spectroscopy and density functional theory calculations. The adiabatic and vertical detachment energies of VnC2(-) and VnC4(-) (n = 1-6) clusters were obtained from their photoelectron spectra. The most stable structures were identified by comparing the results of our calculations with the experimental data. We found that the carbon atoms of VnC2(-/0) and VnC4(-/0) (n = 1-6) clusters were separated gradually with increasing number of vanadium atoms. For VnC2(-/0) (n = 3-6) and VnC4(-/0) (n = 4-6) clusters, the carbon atoms are separated by the vanadium atoms. The geometry of V4C4 is a cubic structure and the geometries of V5C4 and V6C4 are formed by one and two vanadium atoms capping the cubic V4C4 structure, respectively.

Facile N≡N Bond Cleavage by Anionic Trimetallic Clusters V3−xTaxC4− (x=0–3): A DFT Study

“…These structures can be divided into two series: V‐series (V−V 2− x Ta x C 4 − ) and Ta‐series (Ta−V 2− x Ta x C 4 − ) ( x =0, 1, 2) with a V or Ta atom at Site 1, respectively. V 3 C 4 − (i. e., V−V 2 C 4 − ) has a high symmetry (C 2v ) and is composed of three metal atoms in a triangular plane and two C 2 ligands in the upper and lower positions of the plane, which is consistent with studies of Yuan and Li et al [12b,25] . Then, by continuously replacing V by Ta at different sites of V 3 C 4 − , V 3− x Ta x C 4 − ( x= 1–3) clusters were obtained.…”

“…Yuan et al . calculated geometric structures of V n C 2 −/0 and V n C 4 −/0 ( n =1–6) clusters by global optimization with BPW91 functional and 6‐311+G* basis set and the results compared well to experimental photoelectron spectra [25] . Li et al .…”

“…DFT calculations were performed using Gaussian 09 program [24] with BPW91 functional. This functional was chosen since it has been adopted in previous studies on similar systems [12b,25] . Yuan et al .…”

A Facile N≡N Bond Cleavage by the Trinuclear Metal Center in Vanadium Carbide Cluster Anions V3C4–

“…The 495 nm photoelectron spectrum of V 3 C 4 − (Figure 3a) has three major features centered at 1.57, 2.13, and 2.40 eV. The first two features of the spectrum are consistent with those of the 266 nm spectrum of V 3 C 4 − reported by Yuan et al 66 Furthermore, a well-resolved vibrational progression with a peak spacing of 339 ± 20 cm −1 for V 3 C 4 − (Figure 3c) was observed in the 707 nm spectrum, which is very helpful for characterizing the structure. The quantum chemistry calculations predicted that the lowestlying isomer ( 1 R1) of V 3 C 4 − has a sandwich structure containing a V 3 triangular unit and two C 2 ligands, as shown in Figure 3i.…”

Contributions of Nearly-Degenerate States to the Photoelectron Spectra of the Vanadium Dicarbide Anion

“…At two energy levels of laser photons (532 and 355 nm), several low-lying states of the neutral VC 2 were detected (as bands X, A, B, and C), for which vibrational frequencies and detachment energies were reported. Very recently, the photoelectron spectra of VC 2 – have been measured again at a higher level of photon energy (266 mm), which revealed two new bands with higher ionization energies. Hence, these bands can be noted as D and E according to increasing ionization energy (Figure ).…”