Diagram of molecular orbitals for an octahedral center. charge transfer transitions are shown by arrows: strong dipole-allowed and by thick solid arrows; weak dipole-allowed and by thin solid arrows; and, weak dipole-forbidden low-energy transitions by thin dashed arrows.
Two-site dipole matrix elements as a function of separation. The arrow near 4 a.u. points to typical separations. For illustration we choose both relatively large integrals governed by the -bond and the relatively small ones and governed by the -bond. We make use of hydrogen-like radial wave functions with Clementi-Raimondi effective charges37 and typical for the ion.
Theoretical simulation of the overall CT band in . Top panel shows the partial contributions of different dipole-allowed transitions. Bottom panel presents the overall contribution of the dipole-allowed CT transitions to the imaginary part of dielectric function. Insert: experimental spectrum from Okimoto et al. 41 (see text for details).
Spectral dependences of the real and imaginary parts of the dielectric function for orthorhombic .
Spectral dependences of the real and imaginary parts (dotted and solid lines, respectively) of the dielectric functions (a) and (b) for hexagonal .
Real (a) and imaginary (b) parts of the dielectric function in . Arrows show the positions of Lorentzian oscillators.
(Color online) The dielectric functions and the contributing modes in (a). Inset: absorption and refraction indices. The dielectric function in orthoferrite (b).
(Color online) The dielectric function spectra in orthoferrite for three main polarizations. Insets show indices of absorption and refraction. Note, that the region below is not shown because of strong interference effects, which occur due to the high transparency of the samples in this region.
(Color online) The dielectric function spectra of hematite (a) and gallium-substituted hematite with (b, c).
(Color online) The dielectric function spectra of for the three main polarizations. Insets: absorption and refraction indices.
(Color online) The dielectric function spectra of several ferrites with octahedral and tetrahedral centers: lithium ferrite (a), hexaferrite (b), rare earth garnet (c). For the spectra were measured for a single crystal (SC) and a polycrystalline thin film (film).
(Color online) The dielectric function spectra in calcium ferrite for three main polarizations. Insets: absorption and refraction indices.
Spectral dependence of the absorption coefficient for orthoferrite .
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