Collisional Energy Conversion in Polyatomic Molecules

印第安纳大学的Charles Parmenter得到了实验物理化学项目的资助，该项目的目的是进行从大的多原子分子到气相中的原子和双原子分子的振动和转动能量转移的实验。激光泵浦将产生具有态-态分辨率的内部激发，而色散荧光将沿着重要的能量传递通道。要研究的体系是：(1)激光定向乙二醛和重氢甲醛与氢、氦和重氢的碰撞，以研究取向的影响；(2)大分子(以对二氟苯为例)的气体(如Ar)的碰撞激活/失活，其中有足够的内能发生解离和异构化。后一项研究涉及到高激发态分子绝对反应截面的测定，这在以前是不可能的。所提出的研究将对我们理解能量如何从大分子转移到其他原子和小分子，特别是内能到运动能的转换产生重大影响。这些复杂和非常基础的研究将确定这些过程的效率，以及能量传递过程如何受到取向的影响。它们与与大气化学有关的高度兴奋的物种有关。

Charles Parmenter of Indiana University is supported by a grant from the Experimental Physical Chemistry Program to perform experiments on vibrational and rotational energy transfer from large polyatomic molecules to atoms and diatomic molecules in the gas phase. Laser pumping will be used to produce the internal excitation with state to state resolution while dispersed fluorescence will follow the important energy transfer channels. The systems to be studied are: (1) collisions of laser aligned glyoxal and deuterated formaldehyde with hydrogen, helium and deuterium to investigate the effects of orientation; and (2) collisional activation/deactivation by gases such as argon of large molecules (p-difluorobenzene is a prime example) where there is enough internal energy for dissociation and isomerization to occur. This latter study involves the determination of absolute reaction cross sections for highly excited molecules which has not previously been possible.The proposed studies will have a major impact on our understanding of how energy is transferred from large molecules to other atoms and smaller molecules, especially the conversion of internal energy into energy of motion. These sophisticated and very fundamental studies will determine the efficiency of the processes and how the energy transfer process is influenced by orientation. They have relevance to highly excited species associated with atmospheric chemistry.