Lifetime and electronic state interference and ultrafast dissociation of inner-shell resonant Raman excited CO, NO, CO2, and N2O investigated by photon-induced fragment-fluorescence spectrometry (PIFS)

分子在同步辐射激发后的内壳共振衰变过程（电子发射过程，如俄歇/双俄歇衰变或超快解离过程，如库仑爆炸）是基础量子力学测试的原型，因此是当前研究的热点。在本项目中，这些衰变过程的两个方面将以一种新的实验方法进行研究，其中小带宽单色化同步辐射激发与高分辨率（分散）片段荧光光谱法和偏振法（光子诱导荧光光谱法，PIFS）一起使用，以确定作为激发光子能量函数的绝对片段状态选择碎片横截面：1)寿命振动干扰（LVI）和电子态干扰（ESI）效应；2)超快解离。这种迄今很少应用的实验方法将与一个合作小组精心设计的从头计算相结合，以便在实验和理论之间进行定量比较。分子内壳共振的衰减受到寿命振动干涉（LVI）和电子态干涉（ESI）的强烈影响，这是由于邻近的振动或电子共振态在其自然线宽内部分重叠。PIFS实验将部分结合发射荧光的极化分析，用于研究内壳层共振激发的杂原子分子CO和NO中的LVI和ESI。对于这些分子，可以比较受LVI和ESI效应（O1s电子激发）强烈影响的内壳层共振衰减与受影响较弱的共振衰减（CO或NO中分别受C1s或N1s电子激发）。通过色散监测激发中性碎片的荧光发射，研究了内壳共振的超快解离过程。这些碎片不能由库仑爆炸机制发射，表明了一个非常快速的解离过程，与丰富的自电离机制竞争共振的去激发。最后，我们将开始研究三原子分子CO2和N2O在振动态选择性内壳激发C1s （N1s）和O1s电子进入分子激发CO+ （N2+和NO+）片段后的破碎过程，通过在已知波长范围内分散记录CO+ （N2+和NO+）荧光，从而对CO+ （N2+和NO+）片段状态进行状态选择。

Inner-shell resonance decay processes of molecules after their excitation by synchrotron radiation (electron emission processes, like Auger/double Auger decays or ultrafast dissociative processes, like Coulomb explosion) are prototypes for the test of basic quantum mechanics and are, therefore, the topic of intense current research. In the present project two aspects of these decay processes will be investigated in a fresh experimental approach, where excitation by small bandwidth monochromatized synchrotron radiation is used together with high resolution (dispersed) fragment fluorescence spectrometry and polarimetry (photon-induced fluorescence spectrometry, PIFS) to determine absolute fragment-state selective fragmentation cross sections as functions of the exciting-photon energy: 1) Lifetime vibrational interference (LVI) and electronic state interference (ESI) effects, and 2) ultrafast dissociation. This as yet very scarcely applied experimental approach will be combined with elaborate ab-initio calculations by a co-operating group for a quantitative comparison between experiment and theory. The decays of molecular inner shell resonances are strongly influenced by lifetime vibrational interference (LVI) and electronic state interference (ESI), due to closely neighbouring vibronic or electronic resonant states, overlapping partly within their natural linewidths. PIFS experiments, partly with polarization analysis of the emitted fluorescence, will be used to investigate experimentally LVI and ESI in the inner-shell resonantly excited heteroatomic molecules CO and NO. For these molecules it is possible to compare the decay of inner shell resonances strongly influenced by LVI and ESI effects (excitation of the O1s electron) with the decay of resonances weaker influenced (excitation of the C1s or N1s electron in CO or NO, respectively). Ultrafast dissociation processes of the inner-shell resonances will be investigated by dispersively monitoring the fluorescence emission of excited neutral fragments. These fragments cannot be emitted by the Coulomb explosion mechanism and are an indication of a very fast dissociation process competing with the abundant autoionization mechanisms for the deexcitation of the resonances. Finally, we will start to investigate fragmentation processes of the triatomic molecules CO2 and N2O after vibration-state selective inner-shell excitation of the C1s (N1s) and O1s electrons into molecular excited CO+ (N2+ and NO+) fragments by recording dispersedly CO+ (N2+ and NO+) fluorescence in well-known wavelength ranges, being therefore state-selective to the CO+ (N2+ and NO+) fragment state.