Theoretical study of the stereodynamics of CO collisions with CH3- and CF3-terminated alkanethiolate self-assembled monolayers.
Theoretical study of the stereodynamics of CO collisions with CH3- and CF3-terminated alkanethiolate self-assembled monolayers.
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CO 与 CH3 和 CF3 封端的烷硫醇自组装单层碰撞的立体动力学的理论研究。
DOI：
10.1021/jp810557m
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Diego Troya
中科院分区：
文献类型：
--
作者：
W. Alexander;J. R. Morris;Diego Troya
我们提出了一个经典的轨道研究CO碰撞与常规（CH 3-终止）和ω-氟化（CF 3-终止）烷乙氧基化物自组装单分子膜（SAMs），重点分析的立体动力学性质的碰撞。CO分子以相对于表面法线30度或60度的入射角和60 kJ × mol（-1）的碰撞能散射，我们分析了最终的平移和旋转能量、碰撞机制以及旋转角动量的取向和排列。在最初旋转冷CO的碰撞中的最终旋转角动量的对齐分析表明，轻微的偏好“侧手翻”和“螺旋”旋转运动。与此相反，最初激发的CO碰撞稍微有利于“直升机”运动的反冲分子。此外，最终取向的研究表明，虽然侧手翻“上旋”运动是有利于碰撞中，最初冷CO成为旋转激发，没有首选的手性观察时，CO离开的表面与“直升机”运动。涉及初始旋转激发的CO，其中初始旋转角动量对齐和/或定向的轨迹的分析示出了初始旋转运动对能量转移的动力学的不可忽略的影响。例如，一氧化碳接近自组装分子与直升机运动保留了较大的部分，其初始旋转比碰撞侧手翻式运动的分子。与侧手翻或随机运动相比，直升机的初始旋转角动量矢量的排列和方向的守恒也得到加强。两种SAM的立体动力学性质的计算趋势表明，CH 3-SAM比CF 3-SAM更有效地波纹化。
We present a classical-trajectory study of CO collisions with regular (CH3-terminated) and omega-fluorinated (CF3-terminated) alkanethiol self-assembled monolayers (SAMs) with a focus on analyzing the stereodynamics properties of the collision. The CO molecule is scattered with incident angles of either 30 degrees or 60 degrees with respect to the surface normal and with 60 kJ x mol(-1) collision energy, and we analyze final translational and rotational energy, mechanism of the collisions, and orientation and alignment of the rotational angular momentum. Analysis of the alignment of the final rotational angular momentum in collisions involving initially rotationally cold CO indicates a slight preference for "cartwheel" and "corkscrew" rotational motions. In contrast, collisions of initially excited CO slightly favor "helicopter" motion of the recoiling molecule. Moreover, studies of final orientation reveal that, while cartwheel "topspin" motion is favored for collisions in which initially cold CO becomes rotationally excited, no preferred handedness is observed when CO leaves the surfaces with "helicopter" motion. Analysis of trajectories involving initially rotationally excited CO in which the initial rotational angular momentum is aligned and/or oriented shows a non-negligible effect of the initial rotational motion on the dynamics of energy transfer. For instance, CO approaching the SAMs with helicopter motion retains a larger fraction of its initial rotation than molecules colliding with cartwheel-type motions. Conservation of the alignment and orientation of the initial rotational angular momentum vector is also enhanced with helicopter motion relative to cartwheel or random motions. The calculated trends in the stereodynamic properties for the two SAMs indicate that the CH3-SAM is effectively more corrugated than the CF3-SAM.