A comparative study of DFT functionals and basis sets for describing the luminescent spectra of hexacoordinated silicon complexes

This article presents a comparative study of DFT functionals - B3LYP, BHandHLYP and CAM-B3LYP in combination with basis sets - 6-311++g(d,p), cc-pVDZ and cc-pVTZ to describe the luminescence spectra of optimized structures of neutral hexacoordinated silicon complexes. The calculation accuracy of an obtained theoretical data of an electronic absorption spectra of the structures was compared with the known experimental data. To perform comparative calculations with the experimental values, a neutral optimized structure of hexacoordinated Si(bzimpy) 2 complex containing 2,6-bis(benzimidazol-2'-yl)pyridine ligand was considered. A comparison of the absorption spectra of the Si(bzimpy) 2 structure showed that the use of the 6311++g(d,p) basis set in combination with the B3LYP functional gives the best agreement with the experimental data. Based on the obtained results of the study, a comparison was made of the absorption spectra of other silicon compounds - Si(bzimpyMeO)2, Si(bzimpyMe2) 2 and Si(bzimpyMeOMe2)2. Comparative graphs of the structures showed the proximity of the location of intense peaks for all four structures. Thus, we can say that the B3LYP functional gives the best agreement with the experimental data for neutral hexacoordinated silicon complexes. Also this shows that in a more detailed study of the absorption spectra, it can be noted that the use of the 6-311++g(d,p) basis set in combination with the B3LYP functional gives the most accurate values.