Collisional Energy Conversion Mechanisms in Polyatomic Vapors

实验物理化学计划将支持查尔斯S。 印第安纳州布卢明顿大学的帕门特继续他的研究， 各种分子中的状态分辨能量转移。 他的主旨是 实验是使用超声波分子束技术， 处于几个非常特殊的旋转状态的分子。 激光泵浦是 然后用来激发分子的第一个单重态电子， 状态，以及由以下物质填充的状态的分散荧光检测 非弹性散射产生单次碰撞的相对截面 能量传递渠道 过去的努力涉及分散乙二醛 (12振动模式）。 期间 在本资助期内，研究者将延长其对乙二醛的研究 与氦或双原子氢的碰撞。 他还将研究 相对横截面作为质心能量的函数， 碰撞伙伴 最后，将进行交叉束实验。 扩展到氘代甲醛，一个与 由于乙二醛的非平面激发电子态， 偶极矩和极端的非谐性在一个积极的振动模式。 本文的研究是针对振动和转动问题 多原子分子中的能量流动。 这是问题的核心 分子如何获得反应所需的活化能。 的 碰撞自由振动能量流是一个基本方面， 高振动分子的离解或异构化 激发

The Experimental Physical Chemistry Program will support Charles S. Parmenter of Indiana University in Bloomington to continue his studies of state-resolved energy transfer in various molecules. The gist of his experiment is to use a supersonic molecular beam technique to generate molecules in a few, very specific rotational states. Laser pumping is then used to excite the molecule to the first singlet electronic excited state, and dispersed fluorescence detection of states populated by inelastic scattering yields relative cross sections for single collision energy transfer channels. Past efforts involved scattering of glyoxal (12 vibrational modes) from rare gases or diatomic molecules. During this funding period, the investigator will extend his studies on glyoxal to collisions with helium or diatomic hydrogen. He will also study relative cross sections as a function of center-of-mass energy between collision partners. Finally, the crossed beam experiments will be extended to deuterated formaldehyde, a molecular system far different from glyoxal due to its nonplanar excited electronic state, presence of a dipole moment and extreme anharmonicity in an active vibrational mode. The research is directed at the problem of vibrational and rotational energy flow within polyatomic molecules. This is central to the problem of how molecules acquire the activation energy needed for reactions. The collision-free vibrational energy flow is a fundamental aspect of dissociation or isomerization of molecules with high vibrational excitation.