Application of DFT for the modeling of the valence region photoelectron spectra of boron and d‐element complexes and macromolecules

Abstract

Using density functional theory (DFT) in conjunction with ultraviolet (UPS) and X‐ray photoelectron spectroscopy (XPS), we investigated a number of complexes and macromolecules. We have shown on a large set of UPS, XPS, and DFT data that the calculated Kohn–Sham energies of organic and metalorganic complexes can be used as approximate ionization energies (IEs). It is possible to evaluate IEs with an accuracy of 0.1 eV with the density functional approximation (DFA) defect approach. This method has been successfully tested on a large number of boron β‐diketonates and d‐metal chelate and sandwich complexes. We interpreted the bands in the valence region of the XP spectra of macromolecular organosilicon compounds in the solid state by taking into account the density of states and the ionization cross‐sections. According to DFT calculation results, the one‐electron states in the valence region of the model compounds correlate with the positions of the spectral band maxima. © 2015 Wiley Periodicals, Inc.

Electronic Structure and Optical Properties of Boron Difluoride Dibenzoylmethane Derivatives

“…It was shown in refs and that in the valence region the KS orbitals can be a good approximation of the Dyson orbitals. That explains a good correlation of experimental and theoretical ionization energies …”

“…Previously, we published results on research of boron difluoride dibenzoylmethanate, BF 2 Dbm, and boron 1,2-dioxiphenylene, BPheO 2 Dbm, using ultraviolet photoelectron spectroscopy (UPS), XPS, and DFT. As we showed in refs − , the DFT and TDDFT approaches make it possible to calculate energies of the electron levels and excited states of β-diketonate boron complexes with a good accuracy, which is a theoretical basis for unambiguous interpretation of the XPS and absorption spectra and for analysis of electronic effects of substitution for a number of BF 2 Dbm derivatives.…”

“…The method of dispersion correction as an add-on to the standard Kohn–Sham density functional theory is also used. The hybrid three-parameter functional B3LYP is successfully used for DFT calculations of boron complexes. − In our review it was shown that the hybrid B3LYP functional − gives good results for investigation of the electronic structure of boron complexes by XPS. On the basis of the use of the B3LYP functional in our previous studies, ,− we also used it in this work.…”

“…The hybrid three-parameter functional B3LYP is successfully used for DFT calculations of boron complexes. − In our review it was shown that the hybrid B3LYP functional − gives good results for investigation of the electronic structure of boron complexes by XPS. On the basis of the use of the B3LYP functional in our previous studies, ,− we also used it in this work. This allows excluding an influence of the functional type on the electronic effects of substitution.…”

“…In the review 28 it was shown that at present the basis set of atomic functions TZVPP comprising polarizing functions is optimal for calculations of the electronic structure of βdiketonate complexes. The use of the basis set TZVP has allowed us to reduce significantly the time consumption on modeling of the asymmetrical structures III−V.…”