EPR investigations of intermediate Jahn-Teller coupling effects forCu2+in MgO and CaO

Defect structure and formation of defect complexes in Cu2+-modified metal oxides derived from a spin-Hamiltonian parameter analysis

“…This effect is illustrated by a comparison with copper-doped CaO and MgO (Cu × Ca,Mg ), as shown in figure 2(ix,x) for numerically simulated spectra [49,50]. Despite the cubic crystal symmetry axially symmetric EPR spectra are observed, which is owing to the Jahn-Teller effect [49][50][51][52]. As compared to the (Cu Zr,Ti − V…”

Coherent tunneling inCu2+- andAg2+-doped MgO andGarcía‐Fernández1, Sousa2, Aramburu3 et al. 2005Phys. Rev. B272250View full textAdd to dashboardCite

“…18 The use of finite clusters for describing the properties of these systems is consistent with the highly localized character of the unpaired electron residing solely in the MO 6 complex formed by the impurity and the six nearest O 2− anions. 4,6,12 In the present calculations a generalized gradient approximation ͑GGA͒ was used for the exchange-correlation functional in the Becke-Perdew form 19 and the basis set of the best quality in the ADF code was employed. A point charge electrostatic potential was included to take into account the influence of the rest of the ions in the host lattice.…”

“…3,8,10 Aside from the actual value of B there are still doubts about other JT parameters characterizing d 9 impurities in cubic oxides like the JT stabilization energy, E JT . So, Guha and Chase 11 and Reynolds et al 12 estimated E JT in the range 5500-12 000 cm −1 for Cu 2+ -and Ag 2+ -doped MgO and CaO while from the spin-lattice relaxation time, T 1 , a much lower value E JT Ϸ 300 cm −1 was derived. 13 In the case of the excited E g state of MgO : Fe 2+ Hjortsberg et al…”

Unraveling the Coordination Geometry of Copper(II) Ions in Aqueous Solution through Absorption Intensity

“…Thus, the Cu 2+ ion forms D 4h distorted complexes even if Cu 2+ is forced to occupy an O h site in cubic lattices like CaO or MgO. [26] In such a case, Cu 2+ exhibits a local D 4h symmetry with the distortion axes pointing along either x, y, or z directions with the same probability, preserving the overall O h symmetry (triply topological or dynamical degeneracy). Besides the JT effect, additional second-order couplings to odd parity vibrations of a 2u symmetry may yield vibrational mode hardening (positive coupling) or off-center Cu 2+ stabilization (negative coupling).…”