OH自由基的高精度量子化学研究  

Highly Accurate Quantum Chemical Study of the OH Radical

作　　者：马海涛[1] 边文生[2] 郑世钧[1] 孟令鹏[1] 

机构地区：[1]河北师范大学化学学院计算量化研究所,石家庄050091 [2]中国科学院化学研究所分子反应动力学国家重点实验室,北京100080

出　　处：《化学学报》2005年第4期263-268,共6页Acta Chimica Sinica

基　　金：国家自然科学基金(No.20073024);河北省自然科学基金(No.B2004000147)

摘　　要：采用内收缩MRCI方法(InternallyContractedMulticonfiguration-ReferenceConfigurationInteraction)研究了OH自由基,计算得到其基态稳定构型的键长是0.09708nm,对应的实验值是0.096966nm,第一激发态的键长是0.10137nm,实验值是0.10121nm.同时得到势能曲线PECs(PotentialEnergyCurve),再分别由Murrell-Sorbie势能函数拟合计算和POLFIT程序计算得到OH自由基在基态X2Π和第一激发态A2Σ+时的光谱数据:平衡振动频率ωe,非谐性常数ωeχe以及高阶修正ωeYe,平衡转动常数Be,振转耦合系数αe,解离能D0和垂直跃迁能量ν00.这些理论计算结果与最新的实验值非常吻合,精确度比前人也有很大提高.其中我们计算得到基态OH(X2Π)的解离能D0=35568.86cm-1,第一激发态OH(A2Σ+)的解离能D0=18953.93cm-1,从第一激发态A2Σ+(ν=0)到基态X2Π(v=0)的垂直跃迁能ν00=32496.42cm-1.Two potential energy curves for the ground electronic state X(2)Pi and the first excited electronic state A(2)Sigma(+) of OH radical have been calculated using the internally contracted multiconfiguration-reference configuration interaction (IC-MRCI) method including Davidson correction. And they were fitted to analytical potential energy functions using the Muffell-Sorbie potential function to deduce the spectroscopic parameters: equilibrium bond length R(e), rotation coupling constant omega(e), anharmonic constant omega(e)chi(e), equilibrium rotation constant B(e) and vibration-rotation coupling constant alpha(e). These constants and higher-order anharmonic constant omega(e)Y(e), were also calculated by POLFIT. Most of the values obtained are in excellent agreement with experimental results. The calculated dissociation energy D(0) for OH(X(2)Pi) is 35568.86 cm(-1), which is in excellent agreement with the recent experimental value (35565+/-30) cm(-1). The calculated dissociation energy D(0) for OH(A(2)Sigma(+)) is 18953.93 cm(-1). The calculated vertically excited energy from the ground state X(2)Pi (v = 0) to the first excited state A(2)Sigma(+) (v = 0) is 32496.42 cm(-1).

关 键 词：基态 激发态 键长 跃迁能 解离 OH 稳定构型 实验 吻合 PEC 

分 类 号：O641[理学—物理化学]