用耦合簇理论及相关一致五重基研究OH(X2H)自由基的光谱性质

摘要

The spectroscopic properties of the OH(x2Ⅱ)radical have been investigated by using the coupledcluster singles-doubles-approximate-triplas[CCSD(T)]theory in combination with the augmented correlationconsistent polarized valence basis set of quintuple-zeta quality(aug-CC-pV5Z).The present De,Re,ωe results areof 4.6225 eV,0.09701 nm,3743.1644 cm-1,respectively,which are in excellent agreement with the measurements.The adiabatic potential energy curve is calculated over the internuclear separation range from 0.06 to 2.45 nm and is fitted into the analytic Murrell-Sorbie function.By comparisons with other theories,the derived spectroscopic constants(ωeχe,αe and Be) show a good accord with the experiments.With the potential obtained at the CCSD(T)/aug-ce-pV5Z levd of theory,fl total of 15 vibrational smtes has been found when J=0 for the first time by numerically solving the radical Schr6dinger equation of nuclear motion.For each vibrational state,the vibrational level,classical turning points and inertial rotation and centrifugal distortion constants are reported.%利用耦合簇理论CCSD(T)和相关一致五重基aug-cc-pV5Z对OH自由基X2H态的光谱性质进行了计算,获得的De,Re和ωe分别为4.6225 ev,0.09701 nm和3743.1644 cm-1,这与实验结果非常相符.在0.06-2.45 nm的核间距范围内对OH(X2Ⅱ)进行单点能计算,并将计算结果拟合成了Murrell-Sorbie函数.利用得到的解析势能函数,首先计算了该自由基的其余3个光谱常数(ωeχe,αe和Be),其结果与实验值也很相符.接着通过求解双原子分子核运动的径向Schr(o)dinger方程,找到了J=0时OH(X2Ⅱ)的全部15个振动态.最后还计算了每一振动态的振动能级、振动经典转折点、惯性转动常数和离心畸变常数.