估计是写错了吧。

请问您解决了吗

PESPES 发表于 2023-3-14 10:23
我也有一个问题，还有文献里经常出现的CCSD(T)-F12b，这是需要做什么修改才能使用的么

貌似在高斯里面你的关键词写的CCSD(T),但是你算完后用GView打开会看见计算方法位置写的就是CCSD(T)-F12b

有没有一种可能，当你使用 CCSD(T)-F12 时，其实是没法得到 CCSD(T)-F12 的能量的，它只会帮你同时计算出 CCSD(T)-F12a 和 CCSD(T)-F12b ...

PESPES 发表于 2023-3-14 10:23
我也有一个问题，还有文献里经常出现的CCSD(T)-F12b，这是需要做什么修改才能使用的么

orca对于f12的处理我不熟悉，但是molpro可以使用f12a和f12b。以下摘抄自molpro手册：

It should be noted that these methods involve approximations and do not yield the exact CCSD-F12 energies. Preliminary experience has shown that the CCSD-F12A method slightly overestimates the correlation energies, while CCSD-F12B underestimates them. For AVDZ or AVTZ basis sets, CCSD-F12A usually gives very good results, but for larger basis sets it may overestimate the basis set limit and converge from below to the limit. Thus, convergence may not be monotonic, and extrapolation of the correlation energies should not be attempted. CCSD-F12B usually converges monotonically from below to the limit and gives best results for AVQZ and larger basis sets. Thus, we currently recommend CCSD-F12A for AVDZ and AVTZ basis sets, and CCSD-F12B for larger basis sets (rarely needed).

ccsd(t)-f12a不属于泛函，是post-hf方法

我也有一个问题，还有文献里经常出现的CCSD(T)-F12b，这是需要做什么修改才能使用的么