Chen Qiaoling, Shang Longbing, Ma Chong-Geng, Duan Chang-Kui
CAS Key Laboratory of Microscale Magnetic Resonance, and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China.
CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China.
Inorg Chem. 2022 Aug 29;61(34):13471-13480. doi: 10.1021/acs.inorgchem.2c01964. Epub 2022 Aug 12.
First-principles calculations based on density functional theory have been performed to investigate the electronic structure, excited-state Jahn-Teller distortion, and photoluminescence of the multielectron system of the strongly covalent tetrahedral coordinated Mn activator in solids. The electronic structure of the T and A/E excited states is analyzed, and Slater's transition-state method and occupation matrix control methodology are applied to deal with the spin contamination in the lower-spin excited states, which is due to the mixing of the ground state of the same spin projection number. In a series of covalent tetrahedral coordinations, the A → T and A/E excitations and the T → A emission energies are obtained and compared to the reported experimental results. The nephelauxetic effect follows O < S ≈ Se < N, and the larger nephelauxetic effect and crystal field strength lead to the red-shifted emission of nitride phosphors. The Jahn-Teller distortion of the T states is dominated by the -type angular distortion of the [Mn] moiety ( being the ligand), which accounts for the small Stokes shift of tetrahedral coordinated Mn. The results show that the ground- and excited-state electronic and geometric structures and the luminescent property of tetrahedral coordinated Mn can be reliably predicted. The method can be further explored to interpret and discriminate the luminescent properties of materials containing a variety of different Mn sites and complexes and even other transition metals.
基于密度泛函理论的第一性原理计算已被用于研究固体中强共价四面体配位的锰激活剂多电子系统的电子结构、激发态 Jahn-Teller 畸变和光致发光。分析了 T 和 A/E 激发态的电子结构，并应用 Slater 过渡态方法和占据矩阵控制方法来处理低自旋激发态中的自旋污染，这是由于相同自旋投影数的基态混合所致。在一系列共价四面体配位中，获得了 A→T 和 A/E 激发以及 T→A 发射能量，并与报道的实验结果进行了比较。 光谱化学序列为 O < S ≈ Se < N，较大的光谱化学序列效应和晶体场强度导致氮化物磷光体的发射红移。T 态的 Jahn-Teller 畸变主要由 [Mn] 部分（为配体）的 - 型角畸变主导，这解释了四面体配位 Mn 的小斯托克斯位移。结果表明，四面体配位 Mn 的基态和激发态电子及几何结构以及发光性质可以得到可靠预测。该方法可进一步探索用于解释和区分含有各种不同 Mn 位点和配合物甚至其他过渡金属的材料的发光性质。
