García-Fernández, P.Sousa Romero, CarmenAramburu, J. A.Barriuso, M. T.Moreno Sereno, Mauricio2010-01-222010-01-2220050163-1829https://hdl.handle.net/2445/10824The observation of coherent tunnelling in Cu2+ - and Ag2+ -doped MgO and CaO:Cu2+ was a crucial discovery in the realm of the Jahn-Teller (JT) effect. The main reasons favoring this dynamic behavior are now clarified through ab initio calculations on Cu2+ - and Ag2+ -doped cubic oxides. Small JT distortions and an unexpected low anharmonicity of the eg JT mode are behind energy barriers smaller than 25 cm-1 derived through CASPT2 calculations for Cu2+ - and Ag2+ -doped MgO and CaO:Cu2+ . The low anharmonicity is shown to come from a strong vibrational coupling of MO610- units (M=Cu,Ag) to the host lattice. The average distance between the d9 impurity and ligands is found to vary significantly on passing from MgO to SrO following to a good extent the lattice parameter.5 p.application/pdfeng(c) The American Physical Society, 2005MaterialsEstructura electrònicaMaterialsElectronic structureinfo:eu-repo/semantics/article528090info:eu-repo/semantics/openAccess