Sanz-Ortiz Marta N, Rodríguez Fernando
MALTA Consolider Team, DCITIMAC, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander, Spain.
J Chem Phys. 2009 Sep 28;131(12):124512. doi: 10.1063/1.3223459.
This work investigates the influence of electron-phonon coupling associated with E tensor product of e and T tensor product of e Jahn-Teller (JT) effect in different transition-metal (TM) ions on de-excitation phenomena through nonradiative multiphonon relaxation, i.e., photoluminescence (PL) quenching. We developed a configurational curve model which is able to predict from the absorption spectrum whether a given JT-TM ion is PL or quenched. The prediction is made on the basis of an adapted Dexter-Klick-Russell parameter for JT systems, defined in terms of spectroscopic parameters through Lambda(JT)=alphaDelta(e)(abs)/E(abs), where Delta(e)(abs) refers to the splitting of the parent octahedral E(g) states by the JT distortion in E tensor product of e (alpha=3/4) or T tensor product of e (alpha=1/4), and E(abs) is the energy of the first absorption band involving electronic transition between E(g) and T(2g). We show that PL in any JT-TM ion occurs whenever Lambda(JT)<0.1 or is quenched if Lambda(JT)>0.2. This result is noteworthy since it allows us to establish structural requirements for the JT-TM ion and the host crystal to be PL. Although PL properties of materials containing TM ions depend on a variety of structural factors such as the electronic configuration, the site symmetry, and the crystal field produced by neighboring atoms, the present model achieves this goal through a simple spectroscopic parameter: Lambda(JT). In this work we correlated the PL properties of different sixfold-coordinated JT systems such as Ti(3+), Cu(2+), Mn(3+), Cr(2+), Fe(2+), Co(3+), and Ni(3+) in halides and oxides with Lambda(JT) obtained from their respective absorption spectra. From this analysis we conclude that depending on the nature of the JT coupling and its strength, PL is either strongly favored or quenched in T tensor product of e while it is mostly quenched in E tensor product of e systems due to the larger JT distortion.
本工作研究了不同过渡金属（TM）离子中与电子 - 声子耦合相关的e张量积和e Jahn - Teller（JT）效应的T张量积对通过非辐射多声子弛豫实现的去激发现象（即光致发光（PL）猝灭）的影响。我们开发了一种构型曲线模型，该模型能够根据吸收光谱预测给定的JT - TM离子是发生PL还是被猝灭。该预测是基于为JT系统适配的德克斯特 - 克里克 - 拉塞尔参数做出的，该参数通过(\Lambda(JT)=\alpha\Delta_{e}(abs)/E(abs))根据光谱参数定义，其中(\Delta_{e}(abs))指在e的E张量积（(\alpha = 3/4)）或e的T张量积（(\alpha = 1/4)）中JT畸变导致的母八面体(E_{g})态的分裂，(E(abs))是涉及(E_{g})和(T_{2g})之间电子跃迁的第一个吸收带的能量。我们表明，只要(\Lambda(JT)<0.1)，任何JT - TM离子都会发生PL，如果(\Lambda(JT)>0.2)则会被猝灭。这一结果值得注意，因为它使我们能够确定JT - TM离子和主体晶体发生PL的结构要求。尽管含TM离子材料的PL性质取决于多种结构因素，如电子构型、位点对称性以及相邻原子产生的晶体场，但本模型通过一个简单的光谱参数(\Lambda(JT))实现了这一目标。在本工作中，我们将卤化物和氧化物中不同六配位JT系统（如(Ti^{3 +})、(Cu^{2 +})、(Mn^{3 +})、(Cr^{2 +})、(Fe^{2 +})、(Co^{3 +})和(Ni^{3 +})）的PL性质与从它们各自吸收光谱中获得的(\Lambda(JT))相关联。通过该分析我们得出结论，取决于JT耦合的性质及其强度，在e的T张量积中PL要么强烈有利要么被猝灭，而在e的E张量积系统中由于较大的JT畸变PL大多被猝灭。
