Structures, simulated photoelectron spectroscopy, and electronic properties of CuASi(A = Sc, Cu, x ≤ 13) clusters: Relatively stable neutral pentagonal bipyramid structures of CuASi.

Structural design and optimization, simulated photoelectron spectroscopy, electronic properties and chemical bond analysis of CuASi(A = Sc, Cu, x ≤ 13) clusters were systematically studied using the PBE scheme to integrate with global search program of ABCluster. Firstly, neutral MS (the most stable structures) of CuASi of the basic 1 + 5 + 1 structures (1 metal + 5 silicons + 1 metal atoms) can be found as the basic units for assembling more lager clusters under the condition of neglecting distortions and minor changes. If the Cu atoms in CuSi(x ≤ 13) systems was replaced by one Sc atom, the geometries of MS will be reconstructed. Compared with the wheel geometries of CuSi and CuSi, CuScSi and CuScSi clusters belong to near-wheel geometries with peripheral metal atoms. The neutral CuScSi and CuSi clusters possess relatively higher stability in all of cluster sizes. A combination of NPA analysis of CuASi, sp of the Cu atom and spd of the Sc atom hybridizations were crucial to the chemical bonds of A-Si in the neutral CuASi clusters. In view of the higher SED value of the CuSi molecule, chemical bond analysis was carried out using MO, HLg and AdNDP analysis. 18 localized bonds and four delocalized bonds can play a positive role for the relative stabilities of neutral pentagonal bipyramid structures of CuSi. Thus, the CuSi cluster with a lager HLg(1.80 eV) may be a good candidate for the basic unit of silicon-based semiconductor material assembly.