Del Valle Juan Carlos, Catalán Javier
Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, C-2-203. E-28049, Cantoblanco, Madrid, Spain.
Phys Chem Chem Phys. 2019 May 15;21(19):10061-10069. doi: 10.1039/c9cp00739c.
This work revises some anomalous cases reported in the literature, which seemingly violate Kasha's rule. To the contrary, apart from azulene, the remaining molecules fulfill Kasha's rule. Kasha's rule must be stated just as in the seminal paper (M. Kasha, Discuss. Faraday Soc., 1950, 9, 14-19): "The emitting electronic level of a given multiplicity is the lowest excited level of that multiplicity". Therefore, Kasha's rule focuses on the emission (photophysics) for complex molecules, in condensed phase, for the absorption of one photon per molecule under photostationary conditions, then a rapid internal conversion and a vibrational relaxation warrant that the corresponding emission comes from the first excited electronic level regardless of which electronic state of equal multiplicity is excited.
这项工作修正了文献中报道的一些看似违反卡沙规则的异常情况。相反，除了薁之外，其余分子均符合卡沙规则。卡沙规则必须如开创性论文（M. 卡沙，《法拉第学会讨论》，1950年，第9卷，第14 - 19页）中所述：“给定多重性的发射电子能级是该多重性的最低激发能级”。因此，卡沙规则关注的是凝聚相中复杂分子的发射（光物理过程），即在光稳态条件下每个分子吸收一个光子后，快速的内转换和振动弛豫确保相应的发射来自第一激发电子能级，而不论激发的是具有相同多重性的哪个电子态。
