ELECTRIC AND MOLECULAR STRUCTURE INVESTIGATION

电学和分子结构研究

• 批准号: 3754168
• 负责人: R MCDIARMID
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3754168
• 关键词: acetone; chemical bond resonance; chemical structure; diene; electronic spectra; molecular asymmetry; molecular energy level; spectrometry; thermodynamics; ultraviolet spectrometry

Optical absorption and polarization-selected 2 photon resonant multiphoton ionization (REMPI) and photoacoustic (PA) spectroscopic measurements on static samples and REMPI measurements on jet cooled samples of norbornadiene have been carried out to interpret the spectrum of this molecule, compare the results obtained by the different techniques, and assess theoretical calculations of the energies and equilibrium geometries of the excited states of the molecule. All three methods detected the structured 3s Rydberg <-X transition of norbornadiene but only the optical measurement could directly detect either of two lower energy diffuse valence transitions of this molecule. Detailed comparisons of the REMPI and PA spectra of the 3s Rydberg/second valence region of the spectrum demonstrated that only the 3s Rydberg transition is directly observable by REMPI spectroscopy. Once excited the 3s Rydberg transition of the molecule rapidly transfers energy to the valence state which then decays rapidly to the ground state by the emission of heat. The excess energy dependence of the decay rate of the 3s Rydberg state was determined. From these results we hypothesize that the valence transition has a small 2 photon cross section. The vibrational substructure of the 3s Rydberg <-X transition of norbornadiene was also analyzed to determine its excited state geometry to the greatest extent possible. The far UV spectrum of acetone was studied by 3-photon REMPI and PA spectroscopies on static and jet-cooled samples. Two of the observed transition were deduced to be coupled by an asymetric vibration of the molecule. The analysis of this spectrum is continuing.

光吸收和偏振选择 2 光子共振 多光子电离 (REMPI) 和光声 (PA) 光谱 静态样品测量和喷射冷却 REMPI 测量 已对降冰片二烯样品进行了光谱分析 该分子，比较不同方法获得的结果 技术，并评估能量的理论计算和 分子激发态的平衡几何形状。 全部三个 方法检测到的结构化 3s Rydberg <-X 跃迁 降冰片二烯但只有光学测量才能直接检测 该分子的两个较低能量扩散价态跃迁之一。 3s Rydberg/秒的 REMPI 和 PA 光谱的详细比较 光谱的价区表明只有 3s Rydberg 跃迁可通过 REMPI 光谱直接观察到。 曾经兴奋过 分子的 3s 里德伯跃迁迅速将能量转移到 价态然后迅速衰减到基态 热量的散发。 衰减率对过剩能量的依赖性 3s 里德伯状态确定。 根据这些结果我们假设 价态跃迁具有较小的 2 光子横截面。 这 3s Rydberg <-X 转变的振动子结构 还分析了降冰片二烯以确定其激发态几何形状 尽最大可能。 用三光子REMPI和PA研究了丙酮的远紫外光谱 静态和喷射冷却样品的光谱分析。 观察到的两个 推断过渡是通过不对称振动耦合的 分子。 对该频谱的分析仍在继续。