ELECTRIC AND MOLECULAR STRUCTURE INVESTIGATION

光吸收与偏振选择双光子共振 多光子电离光声光谱 对静态样品的测量和对喷射冷却的REMPI测量 已进行降冰片二烯样品的光谱解释 比较不同方法得到的结果， 技术，并评估能量的理论计算， 分子激发态的平衡几何构型。 所有三 方法检测到结构化的3s Rydberg <-X跃迁， 降冰片二烯，但只有光学测量可以直接检测 这种分子的两个较低能量的扩散价跃迁中的任一个。 3s Rydberg/second的REMPI和PA谱的详细比较 价区的光谱表明，只有3s里德堡 跃迁可通过REMPI光谱直接观察到。 一旦激活 分子的3s Rydberg跃迁迅速将能量转移到 价态，然后迅速衰减到基态的 热量的散发。 的衰变率的过剩能量的依赖性， 测定了3s里德堡态。 根据这些结果，我们假设， 价跃迁具有小的2光子截面。 的 3s Rydberg <-X跃迁的振动亚结构 还分析了降冰片二烯以确定其激发态几何构型 尽最大的可能。 用三光子共振增强多光子电离（REMPI）和光放大（PA）研究了丙酮的远紫外光谱 静态和喷射冷却样品的光谱。 两个观察 过渡被推断为耦合的非对称振动的 分子。 对这一频谱的分析仍在继续。

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.