Laboratorium für Organische Chemie, ETH Zürich, CH-8093 Zürich, Switzerland.
J Phys Chem A. 2010 Apr 15;114(14):4704-11. doi: 10.1021/jp907524s.
Resonance-enhanced multiphoton ionization combined with electronic ground state depletion spectroscopy of jet-cooled allyl radicals (C(3)H(5)) provides vibronic spectra of the 3s and 3p Rydberg states. Analysis of the vibronic structure following two-photon excitation of rovibrationally cold allyl radicals reveals transitions to the 3p(z) ((2)A(1)) Rydberg state with an electronic origin at 42230 cm(-1). More than 40 transitions to vibrational levels in the partially overlapping spectra of the 3p(y) ((2)B(2)) Rydberg state and the 3s ((2)A(1)) Rydberg state are identified and reassigned on the basis of predictions from ab initio calculations and results and simulations of pulsed-field-ionization zero-kinetic-energy photoelectron spectra obtained recently using resonant multiphoton excitation via selected vibrational levels of these two Rydberg states (J. Chem. Phys. 2009, 131, 014304). Depletion spectroscopy reveals that the transition to the short-lived 3p(x) ((2)B(1)) Rydberg state in vicinity of three-state same symmetry conical intersections predicted theoretically carries most of the oscillator strength of these coupled 3s and 3p Rydberg states. The results allow for the first time to experimentally derive the energetic ordering of the 3p Rydberg states of the allyl radical.
共振增强多光子电离与喷射冷却烯丙基自由基（C(3)H(5)) 的电子基态消耗光谱学相结合，提供了 3s 和 3p 里德伯态的振动态谱。在对旋转冷烯丙基自由基进行双光子激发后，分析振动态结构揭示了向 3p(z) ((2)A(1)) 里德伯态的跃迁，其电子起源于 42230 cm(-1)。在 3p(y) ((2)B(2)) 里德伯态和 3s ((2)A(1)) 里德伯态的部分重叠光谱中，识别并重新分配了超过 40 个跃迁到振动能级的跃迁，这是基于从头算计算的预测以及最近使用通过这些两个里德伯态的选定振动能级进行共振多光子激发获得的脉冲场电离零动能光电子光谱的结果和模拟（J. Chem. Phys. 2009, 131, 014304）。消耗光谱学表明，理论上预测的三态同对称锥形交叉附近的短寿命 3p(x) ((2)B(1)) 里德伯态跃迁携带了这些耦合的 3s 和 3p 里德伯态的大部分振动态强度。这些结果首次允许从实验上推导出烯丙基自由基的 3p 里德伯态的能级顺序。
