Hydrostatic Pressure Effects on the Triplet Relaxed Excited States of KI: Tl⁺-Type Phosphors through the Quadratic Jahn-Teller Interaction

抄録

Pressure effects on the emission spectra excited by the A absorption have been observed at various temperatures between 168 and 293 K in KI, KBr, and KCl doped with Tl⁺, In⁺, or Ga⁺. When both of the A_T and A_X bands appear, the A_T band grows at the expense of the A_X band as the pressure increases. Particularly, in KBr: Tl⁺ and KBr: In⁺, the A_X band disappears almost completely under 7.5 k bar. When only the A_T band appears as in KCl: Tl⁺ and KCl: In⁺, no drastic change has been observed up to 7.5 k bar. The pressure effects have been discussed on the basis of the quadratic Jahn-Teller effect by correlating the relaxed excited states for the A_T and A_X bands to the tetragonal and trigonal minima on the Γ₄⁻ (A) and Γ₁⁻ adiabatic potential energy surfaces respectively.