Photoelectron spectroscopy, mass spectrometry and electron–ion coincidence experiments combined with tunable synchrotron radiation have been used to study the decay and fragmentation of 2Cl-pyrimidine after Cl(2p), C(1s) and N(1s) excitations. The goal is to investigate how the state- and site-selected excitation and the chemical environment affect the fragmentation paths of the molecule and to make a comparison with fragmentation induced by direct valence ionization. It has been found that the site-selective inner shell excitation affects the branching ratio of the fragments, while the particular fragmentation channels of the cation are determined by the final state populated in the resonant decay of the core excited states. Effects of nuclear motion in the core excited states and the possible ultrafast molecular dissociation following the Cl(2p → σ ^*) core excitation are discussed.

光电子能谱，质谱和电子离子重合实验与可调同步加速器辐射相结合已用于研究2Cl-嘧啶在Cl（2p），C（1s）和N（1s）激发后的衰变和断裂。目的是研究状态和位点选择的激发以及化学环境如何影响分子的碎裂路径，并与直接价电离引起的碎裂进行比较。已经发现，位点选择性内壳激发影响片段的分支比，而阳离子的特定片段化通道是由核心激发态的共振衰变中填充的最终状态决定的。 讨论了σ ^*）磁心激励。