S+OH反应非绝热势能面的构建和动力学研究

The HSO system has been the research hotspot for the physicists and chemists due to its important role in the environmental problems and ozone depletion. It is essential to perform theoretical study on the HSO system because experiments with two radicals are difficult to perform. Potential energy surface is primary for theoretical study, however, there was only one reported global potential energy surface for the HSO system, and the predicted rate constant is four times smaller than the experiment. The deviation between the calculated and experimental result is likely caused by three factors: few geometries; computational inaccuracy and neglect of nonadiabatic effects. We intend to develop a new global diabatic potential energy surface for HSO system based on high-level ab initio calculations, including the ground state and two excited states and their nonadiabatic coupling between them. Three-dimensional cubic spline interpolation will be used to fit the potential energy surfaces. Then, time-dependent wavepacket calculations will be performed to calculate the reaction probability, integral cross section and rate constant which will be compared with the experimental rate constant. The obtained spin-orbit coupling, electrostatic coupling and Coriolis coupling on the S+OH reaction dynamics will supply more information for the S+OH reaction, furthermore, they are the basis of state-to-state dynamics and the supplement of the experiment.

HSO体系在环境问题及臭氧分解过程中具有重要作用，因此一直是物理学家和化学家们研究的热点。由于S+OH反应在实验上较难观测，因此该体系需要借助理论来研究。理论研究需要势能面，到目前为止，只有一个S+OH反应的基态全维势能面报道，在该势能面上的理论计算速率常数比实验值小四倍。导致该差别的主要原因是：势能面选点太少；计算精度低和未考虑非绝热效应。我们拟用更高的计算精度和选用更多的点来构造一个高精度的全维非绝热势能面，计算基态和两个激发态的能量及它们之间的非绝热耦合，拟合方法是三次样条插值。然后用含时量子波包法计算反应几率，反应截面和速率常数，并跟实验值作比较。通过理论计算自旋轨道耦合，静电耦合，Coriolis耦合对反应的影响，为S+OH反应提供更多的信息。此项目将为S+OH反应的态态动力学研究提供必要的基础，为实验提供有力的支撑。

HSO体系在环境问题及臭氧分解过程中具有重要作用，因此一直是物理学家和化学家们研究的热点。到目前为止，只有一个S+OH反应的基态全维势能面报道，在该势能面上的理论计算速率常数比实验值小四倍。导致该差别的主要原因是：势能面选点太少；计算精度低和未考虑非绝热效应。本项目我们用更高的计算精度和选用更多的点来构造一个高精度的全维基态势能面。基组H=av5z,O=av5z,S=aug-cc-pV(5+d)Z，一共选点20576个点，拟合方法是三次样条插值。最后用含时量子波包法计算反应几率，反应截面和速率常数，并跟实验值作比较。我们对NH + D → N + HD，O + D2→OD+ + D，C +( 2P) + H2 (D2 ,HD) → CH + (CD + ) + H(D) 反应进行了含时波包动力学计算，计算了反应几率，反应截面和速率常数，这对研究S+OH反应具有重要的指导意义。