An Open-Shell Superatom Cluster Ta10-with Enhanced Stability by United d-d π Bonds and d-Orbital Superatomic States

We carried out a comprehensive study on the gas-phase reactions of Tan- (n = 5-27) with nitrogen using a customized reflection time-of-flight mass spectrometer coupled with a velocity map imaging apparatus (Re-TOFMS-VMI). Among the studied tantalum clusters, Ta10- exhibits prominent mass abundance indicative of its unique inertness. DFT calculation results revealed a D4d bipyramidal prolate structure of the most stable Ta10- , which was verified by photoelectron spectroscopy experiments. The calculations also unveiled that Ta10- has the largest HOMO-LUMO gap and second-order difference of binding energy among the studied clusters. This is associated with its well-organized superatomic orbitals, which consist of both 6s and 5d orbitals of tantalum atoms, allowing for splitting of superatomic 1D and 2P orbitals and an enlarged gap between the singly occupied molecular orbital (SOMO) and unoccupied beta counterpart, which brings forth stabilization energy pertaining to Jahn-Teller distortion. Also, the SOMO exhibits a united d-d pi orbital pattern that embraces the central Ta8- moiety.

Automated summary

In this study, we conducted a comprehensive investigation on the gas-phase reactions of nitrogen-based tantalum clusters. It was found that Ta10- exhibited inertness and had a stable D4d bipyramidal prolate structure. The organized superatomic orbitals of Ta10- had the largest HOMO-LUMO gap and second-order difference of binding energy, which were associated with Jahn-Teller distortion.