“…The spectra exhibited broad peaks at
409, 956, 1090, 1246, 1396, 1500, 1561, 1589, and 1630 nm that were ascribed to the transitions 6 H 5/2 → 4 L 13/2 , 6 H 5/2 → 6 F 11/2 , 6 H 5/2 → 6 F 9/2 , 6 H 5/2 → 6 F 7/2 , 6 H 5/2 → 6 F 5/2 , 6 H 5/2 → 6 F 3/2 , 6 H 5/2 → 6 H 15/2 , 6 H 5/2 → 6 F 1/2 and 6 H 5/2 → 6 H 13/2 , respectively. All these peaks were due to f–f transitions, and they were consistent with earlier reports [
39–41].…”