AI 中文总结
该研究提出OQVDCD方法，其保留OQVCCD核心性质且标度与CCSD一致，可降低闭壳层反应能计算误差，在强关联体系中能优化OQVCCD能量但收敛性弱于DCSD。
AI 中文摘要
我们提出轨道优化准变分可区分簇双激发（OQVDCD）方法，该方法通过将可区分簇（DC）近似应用于轨道优化准变分耦合簇双激发（OQVCCD）得到。所得方法保留类厄米能量泛函，满足大小可扩展性，在驻点处服从广义Hellmann-Feynman定理，在孤立两电子和两空穴极限下精确，且与耦合簇单双激发（CCSD）的标度同为O(o²v⁴)。针对测试的闭壳层反应能，结果显示OQVDCD将相对于OQVCCD的平均绝对偏差从1.20 kcal/mol降至0.81 kcal/mol，误差接近可区分簇单双激发（DCSD）。在本文考虑的强关联实例中，OQVDCD使OQVCCD能量向基准值偏移，尽管收敛性仍略逊于DCSD。
英文摘要
We present the orbital-optimized quasi-variational distinguishable cluster doubles (OQVDCD) method, obtained by applying the distinguishable cluster (DC) approximation to orbital-optimized quasi-variational coupled cluster doubles (OQVCCD). The resulting method retains a Hermitian-like energy functional, is size-extensive, obeys the generalized Hellmann-Feynman theorem at a stationary point, is exact in the isolated two-electron and two-hole limits, and scales as O(o2v4), like coupled cluster singles and doubles (CCSD). For the tested closed-shell reaction energies, it is shown that OQVDCD reduces the mean absolute deviation relative to OQVCCD from 1.20 to 0.81 kcal/mol, bringing the errors close to distinguishable cluster singles and doubles (DCSD). In the strongly correlated examples considered here, OQVDCD shifts the OQVCCD energies toward the benchmark, although the convergence remains somewhat less robust than for DCSD.
Comments8 pages, 6 figures, 2 tables
