Absorption Spectrum of Optically Pumped Ruby. II. Theoretical Analyses

The absorption spectrum in the excited states of ruby reported by Kushida is analyzed on the basis of the crystalline field or ligand field theory. Remarkably sharp absorption peaks observed in the infrared region are identified to the t 2 g 3 2 E g → t 2 g 3 2 T 2 g transitions, and a temperature-sensitive broad band also in this region is identified to the t 2 g 3 2 T 1 g → t 2 g 3 2 T 2 g transitions. Several broad peaks observed in the visible region are assigned to the t 2 g 3 2 E g → t 2 g 2 ( 3 T 1 g ) e g 2 T 2 g , t 2 g 2 ( 1 T 2 g ) e g 2 T 1 g , t 2 g 2 ( 3 T 1 g ) e g 2 T 1 g , t 2 g 2 ( 1 T 2 g ) e g 2 T 2 g transition. Unidentified broad peaks in the infrared region are discussed in some detail with the assumption that they are due to the phonon-induced electric dipole transitions.