Hrodmarsson Helgi R, Thissen Roland, Dowek Danielle, Garcia Gustavo A, Nahon Laurent, Govers Thomas R
Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin BP 48, Gif-sur-Yvette, France.
Laboratoire de Chimie Physique, Université Paris-Sud, Orsay, France.
Front Chem. 2019 Apr 12;7:222. doi: 10.3389/fchem.2019.00222. eCollection 2019.
Photoelectron/photoion imaging spectrometry employing dispersed VUV radiation from the SOLEIL synchrotron has been used to study the predissociation of N states located up to 1.3 eV above the ion's first dissociation limit. Branching ratios for unimolecular decay into either N or N were obtained by measuring coincidences between threshold electrons and mass-selected product ions, using a supersonic beam of either N or N as photoionization target. The results confirm that predissociation of the state of N is faster than emission to the electronic ground-state by a factor 10 or more for all vibrational levels v' ≥ 3, while for N the two decay modes have comparable probabilities for the levels v' = 3, 4, and 5. In contrast, no significant isotope effect could be observed for the other states of N identified in the photoelectron spectrum. For both N and N isotopologues all vibrational levels of these other states decay to an extent of at least 95% by predissociation.
利用来自SOLEIL同步加速器的分散真空紫外辐射的光电子/光离子成像光谱法，已被用于研究位于离子第一解离极限以上高达1.3 eV的N态的预解离。通过测量阈值电子与质量选择产物离子之间的符合度，以N或N的超声束作为光电离靶，获得了单分子衰变为N或N的分支比。结果证实，对于所有v'≥3的振动能级，N的 态的预解离比发射到电子基态快10倍或更多，而对于N，在v' = 3、4和5能级，两种衰变模式具有相当的概率。相比之下，在光电子能谱中识别出的N的其他态未观察到明显的同位素效应。对于N和N同位素分子，这些其他态的所有振动能级至少95%通过预解离衰变。
