Molecular Collision Dynamics: State Resolved Studies by "Half-Collision" Techniques

Kleiber、Stwalley和Sando教授在实验物理化学项目的支持下，对远翼激光吸收导致碱金属与氢分子相互作用中的化学反应和各种非弹性过程进行了合作实验和理论研究。远翼吸收技术是一种直接探测化学转化中反应物和产物之间通常非常短暂的中间或过渡区域性质的方法。从允许的或禁止的碱金属原子跃迁中调谐到稍微非共振的激光被用来泵送碰撞的碱氢“中间体”，距离适合共振吸收非共振光子。随后分支到各种产品通道被监测，作为激光失谐量的函数，通过发射测量或激光诱导荧光。特别令人感兴趣的是阈值附近的反应动力学和自旋轨道耦合对动力学的影响。理论处理强调近似的经典路径方法，包括原子核的全部运动。对半经典的线展宽理论进行了扩展和推广。

Professors Kleiber, Stwalley, and Sando are supported by the Experimental Physical Chemistry Program in a collaborative experimental and theoretical investigation of far-wing laser absorption leading to chemical reaction and various inelastic processes in alkali metal interactions with hydrogen molecules. The far wing absorption technique is one way in which to probe directly the properties of the usually very short-lived intermediate or transition region between reactants and products in a chemical transformation. A laser tuned slightly off-resonance from an allowed or a forbidden atomic transition of an alkali metal is being used to pump colliding alkali-hydrogen "intermediates" at distances suitable for resonant absorption of the off-resonance photon. The subsequent branching into various product channels is monitored, as a function of the amount of laser detuning, by either emission measurements or laser-induced fluorescence. Of particular interest are reactions dynamics near threshold and the influence of spin-orbit coupling on the dynamics. Theoretical treatments are emphasizing approximate classical path methods that include the full motion of the nuclei. Extensions and generalizations of semiclassical line-broadening theories are being explored.