Pavošević Fabijan, Tao Zhen, Culpitt Tanner, Zhao Luning, Li Xiaosong, Hammes-Schiffer Sharon
Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States.
Department of Chemistry, University of Washington, Seattle, Washington 98195, United States.
J Phys Chem Lett. 2020 Aug 6;11(15):6435-6442. doi: 10.1021/acs.jpclett.0c01891. Epub 2020 Jul 28.
The accurate description of excited vibronic states is important for modeling a wide range of photoinduced processes. The nuclear-electronic orbital (NEO) approach, which treats specified protons on the same level as the electrons, can describe excited electronic-protonic states. Herein the multicomponent equation-of-motion coupled cluster with singles and doubles (NEO-EOM-CCSD) method and its time-domain counterpart, TD-NEO-EOM-CCSD, are developed and implemented. The application of these methods to the HCN molecule highlights their capabilities. These methods predict qualitatively reasonable energies and intensities for a combination band corresponding to simultaneous excitation of two vibrational modes, as well as an overtone. These methods also describe states with double excitation character, such as excited electronic-protonic states corresponding to the simultaneous excitation of an electron and a proton. The ability of the NEO-EOM-CCSD method and its time-dependent counterpart to describe combination bands, overtones, and double excitations will enable a wide range of photochemical applications.
准确描述激发振动态对于模拟广泛的光诱导过程至关重要。核电子轨道（NEO）方法将特定质子与电子置于同一水平进行处理，能够描述激发的电子 - 质子态。本文开发并实现了多组分运动方程耦合簇单双激发（NEO - EOM - CCSD）方法及其时域对应方法TD - NEO - EOM - CCSD。将这些方法应用于HCN分子突出了它们的能力。这些方法定性地预测了对应于两种振动模式同时激发的组合带以及泛音的合理能量和强度。这些方法还描述了具有双激发特征的态，例如对应于电子和质子同时激发的激发电子 - 质子态。NEO - EOM - CCSD方法及其含时对应方法描述组合带、泛音和双激发的能力将推动广泛的光化学应用。
