高圧下における遷移金属化合物の電子状態

Abstract

The discrete variational (DV)-Xce method is applied to the calculation of energies,δEUand δER, of the excitations from the t2g3 4A2g ground state to the t2g2eg4T2g and t2g3 2Eg excited states, respectively, of an octahedral [CrO6]-9 cluster under high pressure. The dependence of these energies upon the Cr-O distance, R, is found to beδ(InδE)δ/(InR) = 4.5,andδ(inδE)/δ(InR) = 0.375The latter dependence gives a good agreement with an empirical relation between the pressure and the spectral shift of the R-emission line of ruby: this relation is used for the pressure calibration.In order to examine the covalency dependence of the shake-up satellite intensity in the photoelectron spectra of transition-metal compounds, a similar DV-Xa calculation is performed for octahedral [NiO6]-10 systems with different Ni-O distances in both the absence and the presence of a 2p hole of Ni. The result shows that the core hole potential is screened out when the system is compressed: the cubic field strength,δ=10Dqd, oes not change even if the hole is created and no shake-up satellite seems to appear.