High-pressure spectroscopy characterisation of LiSc(WO4)2 crystals doped with trivalent chromium

LiSc(WO4)2 crystals doped with trivalent chromium have been investigated using high-pressure spectroscopy. Luminescence spectra between ambient pressure and 260 kbar have exhibited an electronic crossover between the 4T2 and 2E states of Cr3+ and also a two-site feature of Cr3+ ions. We observed a very large blue shift of the 4T2→4A2 emission (about 25 cm−1 kbar−1) and a very large red shift of the 2E→4A2 emission (about −2.5 cm−1 kbar−1) with pressure. In addition, it has been found that pressure induces a decrease of the electron–lattice coupling strength (Sℏω).