Infrared and Raman spectra of the spinel ZnGa2O4

A study of the infrared and Raman spectra of single crystals and powders of ZnGa2O4 yields the following k = 0 phonon frequencies: 175 cm−1 (T1u), 328 cm−1 (T1u), 420 cm−1 (T1u), 570 cm−1 (T1u), 467 cm−1 (T2g), 611 cm−1 (T2g), 638 cm −1 (Eg) and 714 cm−1 (A1g). The results are compared with the frequencies of the vibronic sidebands of the Cr3+ R line emission as observed in ZnGa2O4: Cr3+. It is found that the strogest vibronics of the R lines are due to coupling of the Cr3+ electrons with the T1u modes of the ZnGa2O4 lattice, especially with the two higher frequency T1u modes.