V^(2+)(aq)/V^(3+)(aq)荷移动力学参数的理论研究

Theoretical Study on the Kinetics Parameters of V 2+ (aq)/V 3+ (aq)Electron Transfer Reaction

基于电子转移过程与离子水化过程中的基本共同特征，提出了一种确定电子转移过程动力学参数的精确水化函数方案。利用实验振动光谱数据及水合热力学数据，建立了两种用于描述反应体系与中心离子—内氛水分子分离和溶剂重组之间能量关系的精确水化函数。在提出新的活化模型基础上，结合水化函数给出了活化能的计算方案。利用原始Ｌａｎｄａｕ－Ｚｅｎｅｒ理论计算了电子发射系数。所涉及到的位能面的斜率及耦合矩阵元，采用水化函数、双态模型及数值积分法进行了确定。并计算了Ｖ２＋（ａｑ）／Ｖ３＋（ａｑ）体系的电子转移速率及有关的动力学参数，并与有关的实验值进行了比较，同时讨论了诸模型的可应用性。

On the basis of the common feature of electron transfer and metal ion hydration processes,an accurate hydration potential function scheme for the determination of various electron transfer kinetics parameters is presented.Two hydration potential functions are determined in terms of the experimental spectroscopic data and the hydration thermodynamics data and are then used to depict the energy dependence of the reacting system on the separation between the central ion and the inner sphere molecules,together with the solvent reorganization.The activation energy is obtained in terms of the proposed new activation model and the hydration potential functions,and is calibrated using the corresponding experimental value extracted from the experimental rate constants,and is also compared with those from the other methods.The electronic transmission coefficient is calculated using the Landau Zener formalism.The slopes of the potential energy surfaces are directly obtained from the proposed accurate hydration functions.The coupling matrix element is calculated using the two state model and the numerical integral method over the the Slater type double zeta wave functions obtained using perturbation method.The theoretical value of the electron transfer rate and other parameters for V 2+ (aq)/V 3+ (aq)self exchange system are calculated and are compared with the corresponding experimental values.The applicability of the relevant models are also discussed.