Collision energy dependence of state-to-state differential cross sections for rotationally inelastic scattering of H2O by He.
Collision energy dependence of state-to-state differential cross sections for rotationally inelastic scattering of H2O by He.
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DOI：
10.1039/c6cp06495g
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发表时间：
2017-02
期刊：
影响因子：
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通讯作者：
G. Sarma;A. Saha;C. K. Bishwakarma;Roy J A Scheidsbach;Chung-Hsin Yang;D. Parker;L. Wiesenfeld;U. Buck;L. Mavridis;S. Marinakis
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文献类型：
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作者：
G. Sarma;A. Saha;C. K. Bishwakarma;Roy J A Scheidsbach;Chung-Hsin Yang;D. Parker;L. Wiesenfeld;U. Buck;L. Mavridis;S. Marinakis
在交叉束实验中利用速度图成像技术研究了He在381 ~ 763 cm ~（-1）范围内与H_2O的非弹性散射随碰撞能量的变化关系，能量间隔约为100 cm ~（-1）。通过改变H2O和He束之间的碰撞角度来实现碰撞能量的变化。我们测量了最终转动态JKaKc = 110，111，221和414的散射H2O产物的态-态微分截面（DCS）。利用（2 + 1）共振增强多光子电离（REMPI）技术研究了水分子的转动激发。DCS测量在很宽的范围内的碰撞能量使我们能够探测H2O-He势能面（PES）更详细的比以前的工作。我们发现，一个经典的近似旋转彩虹可以预测碰撞能量依赖的DCS。紧耦合量子力学计算用于产生DCS和部分截面。这里引入了前向-后向比（FBR）来比较实验和理论DCS。理论和实验都表明，碰撞能量的增加伴随着更多的前向散射。
The inelastic scattering of H2O by He as a function of collision energy in the range 381 cm-1 to 763 cm-1 at an energy interval of approximately 100 cm-1 has been investigated in a crossed beam experiment using velocity map imaging. Change in collision energy was achieved by varying the collision angle between the H2O and He beam. We measured the state-to-state differential cross section (DCS) of scattered H2O products for the final rotational states JKaKc = 110, 111, 221 and 414. Rotational excitation of H2O is probed by (2 + 1) resonance enhanced multiphoton ionization (REMPI) spectroscopy. DCS measurements over a wide range of collision energies allowed us to probe the H2O-He potential energy surface (PES) with greater detail than in previous work. We found that a classical approximation of rotational rainbows can predict the collision energy dependence of the DCS. Close-coupling quantum mechanical calculations were used to produce DCS and partial cross sections. The forward-backward ratio (FBR), is introduced here to compare the experimental and theoretical DCS. Both theory and experiments suggest that an increase in the collision energy is accompanied with more forward scattering.