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arXiv 2402.13877physics.chem-phcond-mat.mtrl-scinucl-th
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价电离与卫星跃迁的参考能量

Reference Energies for Valence Ionizations and Satellite Transitions

Antoine Marie, Pierre-François Loos

AI总结:

本文用CIPSI生成小分子体系FCI质量的42个卫星跃迁能和58个价电离势参考值,并据此评估CC层级及$GW$、GF2、$T$矩阵方法。

摘要:

当原子或分子发生电离时,另一个(或多个)电子可能同时被激发。这些同时产生的态被称为“卫星”(或震激跃迁),因为它们在电离谱中表现为较高能量的峰,并且与单粒子电离对应的主峰相比,强度更弱、宽度更大。卫星对应于阳离子物种的电子激发态;由于其相对于中性参考态具有较高的激发程度,使用传统的单参考方法对其进行建模是众所周知的难题。本工作报告了在小分子体系中计算的、具有完全组态相互作用(FCI)质量的42个卫星跃迁能量和58个价电离势。遵循为 quest 数据库制定的协议[Véril 等人,Wiley Interdiscip. Rev.: Comput. Mol. Sci. 2021, 11, e1517],这些参考能量采用迭代微扰选择组态相互作用(CIPSI)方法计算。此外,还依据这些新的精确参考,评估了著名的耦合簇(CC)层级(CC2、CCSD、CC3、CCSDT、CC4和CCSDTQ)的准确性。本文还分析了基于多体格林函数的各种近似($GW$、GF2和$T$矩阵)在电离势方面的表现,并讨论了它们在正确建模卫星跃迁方面的局限性。

英文摘要:

Upon ionization of an atom or a molecule, another electron (or more) can be simultaneously excited. These concurrently generated states are called "satellites" (or shake-up transitions) as they appear in ionization spectra as higher-energy peaks with weaker intensity and larger width than the main peaks associated with single-particle ionizations. Satellites, which correspond to electronically excited states of the cationic species, are notoriously challenging to model using conventional single-reference methods due to their high excitation degree compared to the neutral reference state. This work reports 42 satellite transition energies and 58 valence ionization potentials of full configuration interaction (FCI) quality computed in small molecular systems. Following the protocol developed for the quest database [https://doi.org/10.1002/wcms.1517, Véril et al. Wiley Interdiscip. Rev.: Comput. Mol. Sci. 2021, 11, e1517], these reference energies are computed using the configuration interaction using a perturbative selection made iteratively (CIPSI) method. In addition, the accuracy of the well-known coupled-cluster (CC) hierarchy (CC2, CCSD, CC3, CCSDT, CC4, and CCSDTQ) is gauged against these new accurate references. The performances of various approximations based on many-body Green's functions ($GW$, GF2, and $T$-matrix) for ionization potentials are also analyzed. Their limitations in correctly modeling satellite transitions are discussed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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