Conical intersections induced by classical and quantum light

自由多原子分子在它们的势能面之间表现出丰富的锥形交叉(Cis)。在电子激发(或电离)之后，这些顺式离子对随后的核动力学产生重大影响，从而产生强烈的非绝热效应。顺式也可以由经典(激光)和量子(腔)光诱导，甚至在双原子分子中也是如此。这两种光致顺式(LICI)对多原子分子的影响还很少被研究。这个项目解决了两个主要问题。A)在耦合离子共振态的量子场存在的情况下发生电离。所选择的分子(丁三烯)具有天然的CI，这强烈地影响了自由分子的电离光谱。对天然CI和LICI之间相互作用的研究是该子项目的中心。为了进行比较，还将计算和研究具有激光诱导的LICI的光谱。B)用经典场激发分子后，探测腔内的非绝热动力学。在核动力学过程中，形成的极化电子态是光子-电子态的混合态，腔体可以辐射。重点是研究非绝热动力学，并探讨非绝热动力学与可测量的辐射之间是否存在联系。将研究两个案例，一个(甲醛)不涉及天然CI，另一个(吡嗪)存在天然CI，我们可以调查与LICI的相互作用。由于该项目是关于新的基本效应的，所以选择要研究的系统时，要使它们足够复杂，以验证现象，并充分了解情况，以便进行未来预测所需的准确计算。

Free polyatomic molecules abundantly exhibit conical intersections (CIs) between their potential energy surfaces. Following electronic excitation (or ionization), these CIs have a substantial impact on the ensuing nuclear dynamics leading to strong non-adiabatic effects. CIs can also be induced by classical (laser) and quantum (cavity) light and this even in diatomic molecules. The impact of these two kinds of light-induced CIs (LICIs) has only very little been explored for polyatomic molecules. This project addresses two main issues. a) Ionization in the presence of a quantum field which couples resonantly ionic states. The molecule chosen (butatriene) is known to have a natural CI which strongly affects the ionization spectrum of the free molecule. The investigation of the interplay between the natural CI and the LICI stands in the center of this subproject. For comparison, the spectrum with a LICI induced by a laser field will also be computed and studied. b) Probing non-adiabatic dynamics in a cavity after exciting the molecule by a classical field. The polaritonic states formed are hybrid photonic-electronic states and the cavity can radiate during the nuclear dynamics. The main point is to study the dynamics and, in addition, explore whether there is a relationship between the non-adiabatic dynamics and the radiation which is measureable. Two cases will be studied, one (formaldehyde) where there is no natural CI involved, and one (pyrazine) where a natural CI is present and we can investigate the interplay with the LICI. Since the project is on new fundamental effects, the systems to be studied were chosen such that they are sufficiently complex to validate the phenomena and sufficiently known to allow for accurate calculations needed for future predictions.