ELECTRIC AND MOLECULAR STRUCTURE INVESTIGATION

光吸收和偏振选择双光子共振 多光子电离(REMPI)和光声光谱 静态样品测量和喷射冷却的REMPI测量 用降冰片二烯的样品来解释光谱。 对于这种分子，比较不同的方法得到的结果 技术，并评估能量的理论计算和 分子激发态的平衡几何构型。三个都是 方法检测3S Rydberg&X的结构转变 降冰片二烯但只有光学测量才能直接检测到 该分子的两个较低能量弥散价跃迁中的任何一个。 3S里德堡/秒的REMPI和PA光谱的详细比较 光谱的价区表明，只有3S里德堡 跃迁可以通过REMPI光谱直接观察到。曾经兴奋过 分子的3S里德堡跃迁将能量迅速传递给 价态，然后迅速衰减到基态，通过 放出热量。原子衰减率的超额能量依赖关系 测定了3S里德堡态。根据这些结果，我们假设 价跃迁有一个很小的双光子截面。这个 3S Rydberg&X跃迁的振动子结构 对降冰片二烯进行了分析，确定了其激发态构型 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。两个被观察到的 推导出跃迁是由非对称振动耦合的。 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.