Electronic States of CoSi_n^–/0/+ (n = 1–3) Clusters from Density Matrix Renormalization Group-CASPT2 Calculations

Abstract

Density matrix renormalization group-CASPT2 (DMRG-CASPT2), CASPT2, and density functional theory are employed to describe the complicated geometrical and electronic structures of CoSi n –/0/+ (n = 1–3) clusters. The active spaces of DMRG-CASPT2 are extended to 23 orbitals. The DMRG-CASPT2 method with such large active spaces is reasonable to provide highly accurate relative energies of the electronic states. The pure BP86, PBE, and TPSS functionals appear to be suitable to compute the relative energies of the electronic states of cobalt-doped silicon clusters. The leading configurations, bond distances, vibrational frequencies, normal modes, and relative energies of the electronic states are reported. The electron detachment energies of the removals of one electron from the anionic and neutral clusters are estimated. All six bands in the photoelectron spectrum of CoSi3 – are interpreted based on the computed electron detachment energies and Franck–Condon factor simulations.

Low‐lying states of FeSin−/0/+ (n = 1‐2) clusters from DMRG‐CASPT2 calculations

“…[27,28] The maximum number of renormalized states (m) in the DMRG calculations was set to 1500. [21,23,24] BP86 and B3LYP exchange-correlation functionals in combination with the def2-QZVP basis sets were applied to optimize the geometries and to calculate the harmonic vibrational frequencies of the electronic states. All these calculations were carried out with NWCHEM 7.0.2.…”

“…[15][16][17][18][19][20] This method has already been successfully applied to study the electronic states of several small transition metaldoped silicon and germanium clusters. [21][22][23][24] In this work, DMRG-CASPT2 calculations were carried out to compute the relative energies of the electronic states of FeSin −/0/+ (n = 1-2) clusters. The computational results can serve as a reference for the future experiment research of iron-doped silicon clusters.…”

Unveiling geometric and electronic structures of NbSi4−/0 clusters and electron detachments of the anionic cluster: A quantum chemical investigation

“…Investigating Nb‐doped silicon clusters contributes to a deeper understanding of the microscopic mechanisms in NbSi films and metal‐semiconductor alloys, while providing valuable information for cluster‐assembled material production. The structures and properties of a large number of niobium‐doped silicon clusters have been investigated using both experimental and theoretical methods 5–17 . Regarding the NbSi 4 −/0 clusters, the anionic clusters were synthesized and analyzed using photoelectron spectroscopy with 266 nm wavelength photons 17 .…”

Electron Detachments of NbSin–/0 (n = 1–3) Clusters from Density Matrix Renormalization Group-CASPT2 Calculations

“…In this work, we investigate the electron states of NbSi n –/0/+ ( n = 1–3) clusters using density functional theory (DFT), CASPT2, and the DMRG-CASPT2 methods. With an ability to expand the active space to around 28 orbitals, the DMRG-CASPT2 method is known as an appropriate method for determining the energies of the electronic states of transition-metal-containing compounds. − The DMRG-CASPT2 calculations are expected to provide highly accurate energies for all the relevant electronic states of NbSi n –/0/+ ( n = 1–3) clusters. Electron detachment energies are estimated for the anionic and neutral clusters.…”