Comment on the Crystal-Field Analysis Underlying 'Breakdown of Crystallographic Site Symmetry in Lanthanide-Doped NaYF4 Crystals'

摘要

The crystal-field (CF) analysis and energy-level fittings for Eu3+ ions in - and -NaYF4 by Tu etal. is critically assessed. It is argued that the method used for CF parameter fittings by Tu etal. is inappropriate, thus leading to incorrect numerical results and erroneous interpretation of experimental data.