We present a single-determinant approach to three challenging topics in the chemistry of excited states: double excitations, charge-transfer states, and conical intersections. The results are obtained by using the Initial Maximum Overlap Method (IMOM) which is a modified version of the Maximum Overlap Method (MOM). The new algorithm converges better than the original, especially for these difficult problems. By considering several case studies, we show that a single-determinant framework provides a simple and accurate alternative for modeling excited states in cases where other low-cost methods, such as CIS and TD-DFT, either perform poorly or fail completely.

中文翻译：

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困难电子激励的简单模型

我们对激发态化学中的三个具有挑战性的主题提出了一种单行列式方法：双重激发，电荷转移态和圆锥形相交。通过使用初始最大重叠方法（IMOM）获得的结果，该方法是最大重叠方法（MOM）的修改版本。新算法的收敛性优于原始算法，尤其是对于这些困难的问题。通过考虑几个案例研究，我们表明，在其他低成本方法（例如CIS和TD-DFT）执行不佳或完全失败的情况下，单行列式框架为建模激发态提供了一种简单而准确的替代方法。