Density functional theory % reductions 1 Ca-doped α-Ga2O3 1 Calcium 1 Carbon fibers 1 Charge density distributions 1 Cobalt compounds 1 Complex dielectric functions 1 Cyclic voltammetry 1 Electron affinity 1 Electronic structure 1 Electronic structure and optical properties 1 Energy gap 1 First-principles 1 First-principles study 1 Generalized gradient approximations 1 Group theory 1 High-power transistors 1 Inter-band transition 1 Intermediate spins 1 Light 1 Optical properties 1 Oxidation peak 1 Peak potentials 1 Plane-wave pseudopotential method 1 Polarographic analysis 1 Potential difference 1 Pure α-Ga2O3 1 Re-oxidation 1 Redox chemistry 1