Electronic structure and properties of neutral, anionic and cationic silicon–nitrogen nanoclusters

Abstract

We performed a G3 investigation of the possible stable structures of silicon-nitrogen SinNm clusters where m = 1-4, n = 1-4, m + n = 2-5. We considered the neutral, anionic and cationic molecular species in the singlet, doublet and triplet states, as appropriate. For neutral clusters, our data confirm previous DFT and post Hartree-Fock findings. For charged clusters, our results represent predictions. Several molecular properties related to the experimental data, such as the electronic energy, equilibrium geometry, binding energy (BE), HOMO-LUMO gap (HLG), and spin contamination mathematical left angle bracket S₂ mathematical right angle bracket were computed. We also derived the vertical electron attachment (VEA), the adiabatic electron affinity (AEA), and the vertical ionization energy (VIE), of the neutral clusters. Similar to their carbon-nitrogen counterparts, the lowest energy structures for neutral and cationic silicon-nitrogen clusters are found to be linear or quasilinear. In contrast, anionic silicon-nitrogen clusters tend to form 3D structures as the size of the cluster increases.

icMRCI+Q Study of the Spectroscopic Properties of the 14 Λ-S and 49 Ω States of the SiN− Anion in the Gas Phase

“…Employing the PECs determined by the icMRCI + Q/56 + CV + DK calculations, we evaluated the spectroscopic parameters of 13 Λ-S states. For the purposes of this discussion and due to length limitations, the spectroscopic parameters of the 13 Λ-S states are given in Table S2 , along with the experimental only [ 10 ] and other theoretical [ 11 , 12 , 13 , 14 , 15 , 16 ] spectroscopic results.…”

“…Furthermore, the SiN − anion is a compound of considerable importance in gas-phase ion chemistry [ 6 ], laser-induced plasmas [ 7 ], semiconductor chemistry [ 8 ], and microelectronics [ 9 ]. However, very few experiments [ 10 ] and computations [ 11 , 12 , 13 , 14 , 15 , 16 ] have been conducted for its spectroscopic properties. Based on the aforementioned facts, we systematically investigated the spectroscopic properties of the SiN − anion using a highly accurate ab initio approach.…”

“…Theoretically, only six groups of computations [ 11 , 12 , 13 , 14 , 15 , 16 ] were performed. In 1989, Peterson and Woods [ 11 ] used the Møller–Plesset perturbation theory with single, double, and quadruple substitutions (MP4SDQ) and two large Gaussian basis sets to calculate the AEA (26,826.21 cm −1 ) of SiN and the spectroscopic constants of the SiN − (X 1 Σ + ).…”

“…Their best estimated AEA is 24,212.75 cm −1 . Recently, Mogren et al [ 16 ] used Gaussian-3 theory to study the R e and ω e of the X 1 Σ + state of SiN − . Furthermore, they derived the AEA (25,648.42 cm −1 ) and vertical electron affinity (VEA = 24,115.97 cm −1 ) at the MP2/6-31G* level.…”

“…Furthermore, they derived the AEA (25,648.42 cm −1 ) and vertical electron affinity (VEA = 24,115.97 cm −1 ) at the MP2/6-31G* level. After summarizing these theoretical spectroscopic results [ 11 , 12 , 13 , 14 , 15 , 16 ], we firstly found that all of the calculations were mainly focused on the X 1 Σ + and a 3 Σ + states, and few results achieved high quality. Secondly, it was observed that no spin-orbit coupling (SOC) interactions were involved, though the SOC effect could influence the accurate prediction of spectroscopic properties [ 17 , 18 ].…”