The use of Δ-self-consistent field (SCF) approaches for studying excited electronic states has received a renewed interest in recent years. In this work, the use of this scheme for calculating excited-state vibrational frequencies is examined. Results from Δ-SCF calculations for a set of representative molecules are compared with those obtained using configuration interaction with single substitutions (CIS) and time-dependent density functional theory (TD-DFT) methods. The use of an approximate spin purification model is also considered for cases where the excited-state SCF solution is spin-contaminated. The results of this work demonstrate that an SCF-based description of an excited-state potential energy surface can be an accurate and cost-effective alternative to CIS and TD-DFT methods.

中文翻译：

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良好的振动：使用基态自洽场模型计算激发态频率

近年来，使用 Δ-自洽场 (SCF) 方法研究激发电子态重新引起人们的兴趣。在这项工作中，检查了使用该方案计算激发态振动频率。将一组代表性分子的 Δ-SCF 计算结果与使用配置相互作用与单取代 (CIS) 和时间相关密度泛函理论 (TD-DFT) 方法获得的结果进行比较。对于激发态 SCF 溶液被自旋污染的情况，也考虑使用近似自旋净化模型。这项工作的结果表明，基于 SCF 的激发态势能面描述可以成为 CIS 和 TD-DFT 方法的一种准确且具有成本效益的替代方法。