X-ray absorption spectroscopy studies of YMnO$_{3}$, HoMnO$_{3}$, and Y$_{.4}$Ho$_{.6}$MnO$_{3}$

We have investigated three hexagonal perovskites, YMnO$_{3}$, HoMnO$_{3}$, and Y$_{.4}$Ho$_{.6}$MnO$_{3 }$by O K$_{1}$ and Mn L$_{2,3}$ edge X-ray absorption spectroscopy. In YMnO$_{3}$ and HoMnO$_{3}$ the lowest energy features are predominantly Mn 4p and 3d states with a least five distinct states occurring at approximately the same X-ray energies in both samples. We associate this portion of electronic structure with the trigonal bipyramid bonding symmetry of a five-fold coordinated Mn. Higher energy transitions in the XAS OK$_{1}$ spectra are broader and associated with Ho 5d and Y 4d orbitals. Compared with YMnO$_{3}$ and HoMnO$_{3 }$Mn 3d, and Ho 5d and Y 4d spectral features, the corresponding features in theY$_{.4}$Ho$_{.6}$MnO$_{3}$ O K$_{1}$ spectrum exhibit broader features fewer in number. These are consistent with random alloy bonding in which the Ho and Y are randomly distributed on the A-atom sub-lattice. We will discuss the electronic structure of these empty states in the context of symmetry adapted linear combinations of molecular orbital O 2p*, and Mn 3d*, Ho 5d* and Y 4d* nearest neighbor states.