Optics of Chromites and Charge‐Transfer Transitions

Abstract

Specific features of the charge-transfer (CT) states and O 2p → Cr 3d transitions in the octahedral (CrO 6 ) 9− complex are considered in the cluster approach. The reduced matrix elements of the electric-dipole transition operator are calculated on many-electron wave functions of the complex corresponding to the initial and final states of a CT transition. Modeling the optic spectrum of chromites has yielded a complicated CT band. The model spectrum is in satisfactory agreement with experimental data which demonstrates the limited validity of the generally accepted concept of a simple structure of CT spectra.

Tailoring the bandgap and magnetic properties by bismuth substitution in neodymium chromite

“…The variation of optical absorption edge evidently suggests that Bi (6s 2 ) substituted in the magnetic rare-earth Nd 3+ influences the Cr-O overlap integral. This increase of interaction of Bi cation with oxygen bonds influences the structural distortions through Cr-O polyhedra [41]. Thus, the changes in rotational octahedra distortions observed through Raman scattering measurements and Cr-O changes through optical studies are in good agreement and this distortions that could plausibly be responsible for the observed changes in Neel transition temperatures as well as ferromagnetic nature in these compounds.…”

Visible-light driven Gd2Ti2O7/GdCrO3 composite for hydrogen evolution

“…The optical activity of the GCO is attributed to the charge transfer from O2p-Cr3d in (CrO 6 ) 9octahedral complex. 28, 29 Hence this contributes to the visible light activity of the XGTC composites. From Fig.…”