Enhanced thermal stability in nitrogen-containing gold carbide cages: A DFT study of Au30N20C60 vs. Au30C20C60

Abstract

Two typical deltoidal hexecontahedron-like gold carbide clusters of Au₃₀N₂₀C₆₀ and Au₃₀C₂₀C₆₀ cages have been constructed under BP86/6-31 g(d) for C, N atoms and BP86/def2-TZVPP for Au atoms in this work. No imaginary frequencies have been found in the vibrational frequency analysis for Au₃₀N₂₀C₆₀ and Au₃₀C₂₀C₆₀ cages. The simulated IR and Raman spectrum may also provide theoretical basis for further exploration. Molecular dynamics simulations show that the highest temperature at which Au₃₀N₂₀C₆₀ maintains its original configuration and subunits after 20 ps NVT MD simulations is 1200 K, which is significantly higher than the 900 K observed for Au₃₀C₂₀C₆₀, indicating that the doped N atoms enhance the thermodynamic stability of gold-carbide clusters. The electronic properties of Au₃₀N₂₀C₆₀ has been discussed via density of states, electron density, and adaptive natural density partitioning, which can clearly explain its electronic behavior.