(T) and [T] perturbative corrections are derived for multicomponent coupled-cluster theory with single and double excitations (CCSD). Benchmarking for systems with a single quantum proton shows that multicomponent CCSD methods that include perturbative corrections are more accurate than multicomponent CCSD for the calculation of proton affinities and absolute energies. An approximation is introduced that includes only (T) or [T] contributions from mixed electron–nuclear excitations.

中文翻译：

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(T) 单量子质子多组分耦合团簇理论的修正

(T) 和 [T] 微扰校正是针对具有单激发和双激发 (CCSD) 的多分量耦合簇理论得出的。对具有单个量子质子的系统进行基准测试表明，在计算质子亲和力和绝对能量时，包含微扰校正的多组分 CCSD 方法比多组分 CCSD 更准确。引入的近似值仅包括来自混合电子-核激发的 (T) 或 [T] 贡献。