Optical Spectra ofCr3+Pairs in the Spinel ZnGa2

Spectrum designation and effect of Al substitution on the luminescence of Cr3+ doped ZnGa2O4 nano-sized phosphors

“…2b), which is absent at low temperature. Since the R lines exhibit a large splitting due to the trigonal distortion local environment, the accompanied vibronic peaks should also occurred in pairs [24] with a separation of 42 cm À 1 . Accordingly, some vibronic peaks are determined and labeled in Fig.…”

“…The remaining lines in Fig. 2(a) can be divided into three groups: the lines at 688.75 nm (designated by N 1 ) and 692.25 nm (N 2 ) as ''structure dependent'' lines, 701.5 nm (N 3 ) and 703.5 nm (N 4 ) as ''concentration dependent'' ones [24] and 694.5 nm (G 1 ) as ''impurity host'' one, respectively. The designation will be discussed in the following sections.…”

Optical spectroscopy study of Cr3+ ion in NaMg3Al(MoO4)5 crystal

“…The temperature-dependent optical measurements allow one to obtain more information about the ground-and excited-state exchange splitting. The absorption intensity and excitation signal of the observed lines in the absorption and excitation spectra are proportional to the occupation number n(S) of the level with spin S from which the transition starts [30,37]. Unfortunately, in the NaMg 3 Al(MoO 4 ) 5 :Cr 3+ crystal these absorption and excitation lines are not available because they are covered by intense absorption or excitation bands of the 4 A 2 -4 T 2 transition.…”

Exchange-coupled chromium ion pairs in ruby revisited

“…Since this commutes with the total spin, the states can be classified by the total spin (S ¼ 2, 1) and by their symmetry under interchange (+ or À) of the two ions: 2+, 2À, 1+, 1À. This Hamiltonian has been used by Pryce [12] and van der Ziel [7] to describe the spectroscopy of Cr 3+ pairs in ruby, and by van Gorkam et al [16] in their analysis of the optical spectroscopy of Cr 3+ pairs in ZnGa 2 O 3 . A comprehensive treatment of Cr 3+ pairs coupled by a strong exchange interaction in a site of D 3h symmetry has been given by Dubicki and Tanabe [13] and by Riesen and Gu¨del [14].…”