用准经典轨线方法研究O(1D)+DBr→OD+Br反应的极化分布

运用准经典轨线法结合Peterson 从头计算势能面, 在碰撞能为0.22 eV 时对O(¹D) +DBr(v=0, j=0) → OD+Br 反应进行了细致的立体动力学性质研究. 极化微分反应截面(PDDCSs)给出了反应产物的散射方向. 反映k 与j′ 两矢量相关的函数P(θ_r)的分布表明产物分子的转动角动量j′在垂直于反应物相对速度矢量k 的方向上有强烈的取向分布; 反映k, k′与j′三矢量相关的函数P(ø_r)的分布表明产物转动角动量j′不仅有沿着y 轴的取向效应,还有沿着y 轴负方向的定向效应; 描述产物转动角动量j′的空间分布函数P(θ_r,ø_r)说明反应垂直于散射平面极化. 质量因子的不同, 使得O(¹D)+DBr 反应的极化与O(¹D)+HBr 反应的极化有明显的差异, 说明同位素效应比较明显.

Study on the polarization distribution of the O(1D)+DBr →OD+Br reaction using quasi-classical trajectory method

Theoretical studies of the stereodynamics for the reation O(¹D)+DBr→OD+Br have been carried out using the quasi-classical trajectory method on the ab initio global potential energy surface at 0.22 eV collision energy. The polarization-dependent differential cross-sections (PDDCSs) show the scattering direction of the product. The distribution P(θ_r) of the two vectors correlation between k and j′ shows that the rotational angular momentum polarization of the product molecule is quite strong. The function P(ø_r) which reflects the angle distribution of three vectors correlation k-k′-j′ indicates that j′ is not only aligned, but also oriented preferentially along the negative direction of the y-axis. There are two obvious distributions at (90°, 90°) and (90°, 270°) about the product rotational angular momentum P(θ_r,ø_r), which indicate that the product molecule is preferentially polarized perpendicular to scattering plane. Comparing O(¹D)+DBr reaction with O(¹D)+HBr reaction, it can be seen that the degree of polarization distribution of O(¹D)+DBr reaction is weaker than that of O(¹D)+HBr reaction. That is due to the different quality factor of the two reactions, illuminating that the isotopic effect is relatively evident.