The luminescence of fifteen representative ${\mathrm{Eu}}^{2+}$-doped phosphors used for white-LED and scintillation applications is studied through a constrained density functional theory. Transition energies and Stokes shift are deduced from differences of total energies between the ground and excited states of the systems, in the absorption and emission geometries. The general applicability of such methodology is first assessed: for this representative set, the calculated absolute error with respect to experiment on absorption and emission energies is within 0.3 eV. This set of compounds covers a wide range of transition energies that extents from 1.7 to 3.5 eV. The information gained from the relaxed geometries and total energies is further used to evaluate the thermal barrier for the $4f\text{−}5d$ crossover, the full width at half maximum of the emission spectrum and the temperature shift of the emission peak, using a one-dimensional configuration-coordinate model. The former results indicate that the $4f\text{−}5d$ crossover cannot be the dominant mechanism for the thermal quenching behavior of ${\mathrm{Eu}}^{2+}$-doped phosphors and the latter results are compared to available experimental data and yield a $30\%$ mean absolute relative error. Finally, a semiempirical model used previously for ${\mathrm{Ce}}^{3+}$-doped hosts is adapted to ${\mathrm{Eu}}^{2+}$-doped hosts and gives the absorption and emission energies within 0.9 eV of experiment, underperforming compared to the first-principles calculation.

中文翻译：

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掺杂Eu2 +的磷光体发光的第一性原理研究

十五代表发光 ${\mathrm{欧洲联盟}}^{\mathrm{2个}+}$通过约束密度泛函理论研究了用于白光LED和闪烁应用的掺杂磷光体。过渡能和斯托克斯频移是由吸收和发射几何中系统的基态和激发态之间的总能量之差推导出来的。首先评估这种方法的一般适用性：对于该代表性组，相对于吸收和发射能量的实验，计算出的绝对误差在0.3 eV之内。这组化合物涵盖了从1.7到3.5 eV的范围广泛的跃迁能量。从松弛的几何结构和总能量中获得的信息将进一步用于评估热电势的热障。$4F\text{-}5d$使用一维组态坐标模型，可以计算出发射光谱的一半宽度，发射光谱的半峰全宽和发射峰的温度漂移。以前的结果表明$4F\text{-}5d$ 交叉不能成为合金热淬火行为的主要机制。 ${\mathrm{欧洲联盟}}^{\mathrm{2个}+}$掺杂的磷光体，并将后者的结果与可用的实验数据进行比较，得出 $30％$平均绝对相对误差。最后，以前使用的半经验模型${铈}^{3+}$掺杂的主机适用于 ${\mathrm{欧洲联盟}}^{\mathrm{2个}+}$掺杂的主体，并在0.9 eV的实验范围内提供吸收和发射能量，与第一性原理计算相比表现不佳。