From 5ccd2cd6e7b213975132b48da4a70b86803985fd Mon Sep 17 00:00:00 2001 From: Pierre-Francois Loos Date: Sat, 22 Aug 2020 21:55:38 +0200 Subject: [PATCH] S^2 --- benzene.tex | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/benzene.tex b/benzene.tex index 8c52cbd..1242ca4 100644 --- a/benzene.tex +++ b/benzene.tex @@ -125,7 +125,7 @@ As mentioned above, SCI+PT2 methods rely heavily on extrapolation, especially wh We then linearly extrapolate the total SCI energy to $E_\text{PT2} = 0$ (which effectively corresponds to the FCI limit) using the two largest SCI wave functions. Although it is not possible to provide a theoretically sound error bar, we estimate the extrapolation error by \titou{the difference in excitation energy between the largest SCI wave function and its corresponding extrapolated value.} We believe that it provides a very safe estimate of the extrapolation error. -%Note that all the wave functions are eigenfunctions of the $\Hat{S}^2$ spin operator, as described in Ref.~\onlinecite{Applencourt_2018}. +Note that, unlike excited-state calculations where it is important to enforce that the wave functions are `eigenfunctions of the $\Hat{S}^2$ spin operator, \cite{Applencourt_2018} the present wave functions do not fulfil this property as we aim for the lowest energy of a single state. We have found the $\expval*{\Hat{S}^2}$ is, nonetheless, very close to zero. The corresponding energies are reported in Table \ref{tab:NOvsLO} as functions of the number of determinants in the variational space $N_\text{det}$. A second run has been performed with localized orbitals.