Electron paramagnetic resonance spectral studies on natural sapphire

Electron paramagnetic resonance in gamma-ray, electron and neutron flux irradiated sapphire

“…EPR spectroscopy measures the absorption of microwave radiation by an unpaired electron when it is placed in a strong magnetic field [22]. 002 on Cr 3+ ion [4]. It can be deduced that the Cr 3+ impurity is barely found from the EPR spectroscopy, which is consistent with the previous PIXE result in Ref.…”

“…The longevity and reliability of the material will define the life and durability of the spacecraft. Sapphire is widely used in aerospace optical environment because of its excellent thermal shock resistance, great mechanical properties, low scattering, and superior high-temperature infrared properties [4][5][6][7]. So, it is indispensable for knowledge of its service performance under various space-radiation environments [8,9].…”

Microscopic origin of the optical processes in blue sapphire

“…Although our calculations have confirmed that the intervalence charge transfer mechanism is likely to be responsible for the colour of sapphire, it has been argued that intra-valence transitions in metal impurities themselves are a contributing factor. 9,10,20 It is for this reason that we have calculated the energies of these transitions. The metal impurities whose crystal field parameters we have investigated in sapphire are Cr 3+ , Ti 3+ , Fe 3+ , Fe 2+ , and Ni 2+ .…”