Multiple Resonance Spectroscopy and Molecular Dynamics

在化学系物理化学计划的这个项目中，坦普尔大学的Marjatta Lyyra教授将研究碱原子对之间的长程相互作用，间隔超过10埃，以便绘制出碱性双原子分子离解极限附近的势面。钠分子是要研究的主要物种。通过多次激光激发制备了长程态的分子。一种新的多重共振技术--受激辐射解离，将被用来选择性地研究光解动力学状态作为分子转动和能量的函数，以实现对状态的长程非绝热混合的全面理解。还将研究解离开始时制备的初始核间距与非绝热耦合强度的相关性。作为这项工作的一部分，将开发新的方法来增强对连续波多共振信号的检测。这项研究有助于理解化学反应开始时原子在大核间分离时的行为。在大的核间分离时，许多电子能态通常是紧密间隔的，这使得它们之间的耦合影响了键的断裂光解和成键的缔合电离过程。这项工作中收集的信息将有助于理解当代关于超低温下原子碰撞的研究结果。

In this project in the Physical Chemistry Program of the Chemistry Division, Prof. Marjatta Lyyra of Temple University will investigate the long range interactions, at separations in excess of 10 Angstroms, between pairs of alkali atoms in order to map out the potential surface near the dissociation limit of alkali diatomic molecules. The sodium molecule is the principal species to be investigated. The molecules are prepared in their long range states by multiple laser excitation. A new multiple resonance technique, stimulated radiative dissociation, will be used to study photodissociation dynamics state selectively as function of molecular rotation and and energy in order to achieve full understanding of long range nonadiabatic mixing of states. The correlation of the initial internuclear distance prepared as dissociation begins with the strengths of the nonadiabatic couplings will also be studied. As part of this work new methods will be developed to enhance the detection of continuous wave multiple resonance signals. This research contributes to the understanding of behavior of atoms at large internuclear separations at the onset of chemical reactions. At large internuclear separations many electronic energy states are often closely spaced, making for couplings betwen them which affect the bond-breaking photodissociation, and bond-forming associative ionization processes. The information gathered in this work will be of assistance in understanding the results of contemporary research on atomic collisions at ultra low temperatures.