Molecular Structure and Dynamics Beyond the Born-Oppenheimer Approximation

超越玻恩-奥本海默近似的分子结构和动力学

• 批准号: 9632862
• 负责人: Edward Grant
• 金额: $ 12.45万
• 依托单位: Purdue Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-08-01 至 1997-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9632862&HistoricalAwards=false
• 关键词: Molecular; Structure; Dynamics; Beyond; Born

The Experimental Physical Chemistry Program is supporting Edward R. Grant of Purdue University to continue his research on state-to-state photoionization and the dynamics of intramolecular relaxation in highly excited states of small molecules. Systems to be studied include a set of fundamentally important oxy-hydrocarbon and metal-centered free radicals, relevant as intermediates in air pollution, combustion and electronic materials processing. Multiresonant excitation techniques will be used to make high-resolution spectroscopic measurements of resonant lineshapes and positions for final states coupled to ionization and dissociation continua. These observations will lay an experimental foundation for collaborative theoretical work, designed to achieve a fundamental understanding of the interaction between core-vibrational and extravalent-electronic degrees of freedom, and to determine the source of mode selectivity in the vibrational autoionization of polyatomic molecules. Photoselection and specialized detection methods will also be used to study rovibrational structure in the electronic ground states of cations and precursor free-radicals: zero-kinetic-energy threshold photoionization measurements will establish vibrational-rotational level spectra of closed-shell oxy-hydrocarbon cations, characterizing potential energy surfaces and anharmonic coupling from zero-points to thresholds for intramolecular proton transfer. Similar measurements on Group III hydride cations will follow progressions of vibrational resonances up to and beyond thresholds for diatomic hydrogen elimination. Vibration-rotation spectra obtained by state-to-state photoionization - bleaching methods will address outstanding issues of structure and symmetry in free-radical ground states. The detailed dynamics of energy transfer between electronic and internuclear degrees of freedom has significant practical consequences. In nature, for example, photosynthesis begins with selective intramolecular energy migration, followed by charge separation and electron transfer. In an extension of his previous research effort, Grant will now include studies on main-group free radical systems, chosen for their relevance to thermochemical issues in combustion, atmospheric chemistry and electronic materials processing. As an example, the group III radical hydrides mentioned above are important intermediates in the metallization and p-doping of silicon devices by chemical vapor deposition.

实验物理化学项目正在支持Edward R.格兰特 普渡大学继续他的研究， 光电离和分子内弛豫动力学的高度 小分子的激发态 要研究的系统包括一套 基本上重要的氧烃和金属中心的自由 自由基，作为空气污染、燃烧和 电子材料加工 多共振激发技术 将被用来进行高分辨率的光谱测量， 与电离耦合的终态的共振线形状和位置 和解离连续体 这些观察结果将奠定一个实验 合作理论工作的基础，旨在实现 对核心振动和 额外的电子自由度，并确定来源 多原子振动自电离的模式选择性 分子。 光选择和专门的检测方法也将 用于研究电子基态的振转结构， 阳离子和前体自由基：零动能阈值 光电离测量将建立振动-转动能级 闭壳含氧烃阳离子的光谱，表征电位 能量面和从零点到阈值的非谐耦合 进行分子内质子转移。 对第III组进行类似测量 氢化物阳离子将遵循振动共振的级数， 并且超过双原子氢消除的阈值。 用态-态光电离方法获得的振动-转动光谱 漂白方法将解决结构的突出问题， 自由基基态的对称性 电子和电子之间能量转移的详细动力学 核间自由度具有重大的实际影响。 例如，在自然界中，光合作用开始于选择性的 分子内能量迁移，随后是电荷分离， 电子转移 作为他以前研究工作的延伸， 格兰特现在将包括研究主群自由基系统，选择 因为它们与燃烧、大气中的热化学问题相关， 化学和电子材料加工。 为例 上述第III族自由基是合成的重要中间体， 硅器件的化学气相金属化和p型掺杂 证词