Various Cr³⁺-activated oxide phosphors can be classified into two groups: a strong crystal field group [E(²E_g)_ZPL < E(⁴T_2g)_ZPL] and a weak crystal field group [E(²E_g)_ZPL > E(⁴T_2g)_ZPL] from an equality relation of the zero-phonon line (ZPL) energies of 2E_g and ⁴T_2g. Obtaining reliable Racah parameters for the 3d³ ion (Cr³⁺) usually needs accurate information on the three excited-state ZPL energies, E(²E_g)_ZPL, E(⁴T_2g)_ZPL, and E(⁴T_1g,a)_ZPL. However, an exact determination of such ZPL energies is a very difficult problem. Because of an accumulation with adjacent excited states along with the presence of charge transfer band, this is especially for E(⁴T_1g,a)_ZPL. An importance of accurate determination of the excited-state energies to be used in the Racah parameter calculation is discussed in detail with demonstrating a risk of erroneous conclusion of whether Cr³⁺-activated oxide phosphor belongs to a strong or weak crystal-field phosphor.

各种Cr ³⁺活化的氧化物磷光体可分为两类：强晶场组[ E（² E _g）_ZPL  <  E（⁴ T _{2 g}）_ZPL ]和弱晶场组[ E（² E _g）_ZPL  >  E（⁴ T _{2 g}）_ZPL ]从零声子线（ZPL）能量2 E _g和⁴ T _{2 g}的等式。获得3 d ³离子（Cr ³⁺）的可靠Racah参数通常需要有关三种激发态ZPL能量E（² E _g）_ZPL，E（⁴ T _{2 g}）_ZPL和E（⁴ T _1克，a）_ZPL。但是，准确确定这种ZPL能量是一个非常困难的问题。由于具有相邻激发态的累积以及电荷转移带的存在，这尤其对于E（⁴T _{1 g，a}）_ZPL。详细讨论了精确确定要在Racah参数计算中使用的激发态能量的重要性，并证明了错误结论Cr ³⁺活化的氧化物磷光体属于强场还是弱晶场磷光体。