Tin-oxo cages belong to a class of organometallic compounds which were recently recognized as promising photoresist materials for the extreme ultraviolet (EUV) lithography − a method proposed for the new generation of integrated circuits. The EUV exposure of tin-oxo cages causes significant structural changes; however, the molecular mechanism of these changes is to a large extent unknown. In the present work, we focus on the photoionization dynamics of the small tin-oxo molecules: the trimethlytin hydroxide (TMTH) and trihydroxymethyl stannane (THMS) molecules. We employed the surface hopping (SH) dynamics on the Floating Occupation Molecular Orbital Complete Active Space Configuration Interaction (FOMO-CASCI) potential energy surfaces accelerated with graphical processor units (GPU). After the ionization of both molecules, we observed an ultrafast relaxation (∼100 fs) into the ground and first excited electronic states followed by a rapid dissociation yielding the neutral CH₃ and OH radicals and a charged remainder. However, the dissociation dynamic does not occur solely on the hot ground electronic state and reaction outcome partially depends on initially ionized state. Our work also demonstrate that the SH+FOMO-CASSCI based dynamics is suitable for electron-rich open-shell systems.

锡-氧代笼属于一类有机金属化合物，最近被公认为是极有希望的用于极端紫外线（EUV）光刻的光致抗蚀剂材料-一种用于新一代集成电路的方法。锡-氧笼的EUV暴露会引起结构上的重大变化；然而，这些变化的分子机制在很大程度上尚不清楚。在目前的工作中，我们专注于锡-氧代小分子的光电离动力学：氢氧化三甲基锡（TMTH）和三羟甲基锡（THMS）分子。我们在浮动职业分子轨道完全主动空间构型相互作用上采用了表面跳变（SH）动力学（FOMO-CASCI）的势能面通过图形处理器（GPU）加速。两个分子电离后，我们观察到进入基态和首先激发的电子态的超快弛豫（〜100 fs），然后迅速解离，产生中性CH ₃和OH自由基以及带电的剩余物。然而，解离动力学不仅发生在热基态电子状态，反应结果部分取决于初始电离状态。我们的工作还证明，基于SH + FOMO-CASSCI的动力学适用于富含电子的开壳系统。