revising D2h TBE

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Pierre-Francois Loos 2022-04-08 10:34:38 +02:00
parent 8f4e5df58d
commit c6c0cbcbbe

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@ -575,18 +575,19 @@ CCSDT &6-31+G(d)& $1.442$ & $3.357$ & $4.311$ \\
& aug-cc-pVTZ & $1.411$ & $3.139$ & $4.429$ \\[0.1cm] & aug-cc-pVTZ & $1.411$ & $3.139$ & $4.429$ \\[0.1cm]
CC4 &6-31+G(d)& & $3.343$ & $4.067$ \\ CC4 &6-31+G(d)& & $3.343$ & $4.067$ \\
& aug-cc-pVDZ & & $3.164$ & $4.040$ \\ & aug-cc-pVDZ & & $3.164$ & $4.040$ \\
& aug-cc-pVTZ & & $[3.128]$\fnm[1] & $[4.143]$\fnm[1]\\[0.1cm] & aug-cc-pVTZ & & $[3.128]$\fnm[1] & $[4.032]$\fnm[2]\\[0.1cm]
CCSDTQ &6-31+G(d)& & $3.340$ & $4.073$ \\ CCSDTQ &6-31+G(d)& & $3.340$ & $4.073$ \\
& aug-cc-pVDZ & & $[3.161]$\fnm[2]& $[4.047]$\fnm[2] \\ & aug-cc-pVDZ & & $[3.161]$\fnm[3]& $[4.046]$\fnm[3] \\
& aug-cc-pVTZ & & $[\bf 3.125]$\fnm[3]& $[\bf 4.149]$\fnm[3]\\[0.1cm] & aug-cc-pVTZ & & $[\bf 3.125]$\fnm[4]& $[\bf 4.038]$\fnm[4]\\[0.1cm]
CIPSI &6-31+G(d)& $1.486\pm 0.005$ & $3.348\pm 0.024$ & $4.084\pm 0.012$ \\ CIPSI &6-31+G(d)& $1.486\pm 0.005$ & $3.348\pm 0.024$ & $4.084\pm 0.012$ \\
& aug-cc-pVDZ & $1.458\pm 0.009$ & $3.187\pm 0.035$ & $4.04\pm 0.04$ \\ & aug-cc-pVDZ & $1.458\pm 0.009$ & $3.187\pm 0.035$ & $4.04\pm 0.04$ \\
& aug-cc-pVTZ & $1.461\pm 0.030$ & $3.142\pm 0.035$ & $4.03\pm 0.09$ \\ & aug-cc-pVTZ & $1.461\pm 0.030$ & $3.142\pm 0.035$ & $4.03\pm 0.09$ \\
\end{tabular} \end{tabular}
\end{ruledtabular} \end{ruledtabular}
\fnt[1]{Value obtained using CC4/aug-cc-pVDZ corrected by the difference between CCSDT/aug-cc-pVTZ and CCSDT/aug-cc-pVDZ.} \fnt[1]{Value obtained using CC4/aug-cc-pVDZ corrected by the difference between CCSDT/aug-cc-pVTZ and CCSDT/aug-cc-pVDZ.}
\fnt[2]{Value obtained using CCSDTQ/6-31+G(d) corrected by the difference between CC4/aug-cc-pVDZ and CC4/6-31+G(d).} \fnt[2]{Value obtained using CC4/aug-cc-pVDZ corrected by the difference between PC-NEVPT2(12,12)/aug-cc-pVTZ and PC-NEVPT2(12,12)/aug-cc-pVDZ.}
\fnt[3]{TBE value obtained using CCSDTQ/aug-cc-pVDZ corrected by the difference between CC4/aug-cc-pVTZ and CC4/aug-cc-pVDZ.} \fnt[3]{Value obtained using CCSDTQ/6-31+G(d) corrected by the difference between CC4/aug-cc-pVDZ and CC4/6-31+G(d).}
\fnt[4]{TBE value obtained using CCSDTQ/aug-cc-pVDZ corrected by the difference between CC4/aug-cc-pVTZ and CC4/aug-cc-pVDZ.}
\end{table} \end{table}
\end{squeezetable} \end{squeezetable}
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@ -633,7 +634,7 @@ Using a larger active space resolves most of these issues: CASSCF predicts the c
Finally, for the CC models (Table \ref{tab:D2h}), the two states with a large $\%T_1$ value, {\tBoneg} and {\sBoneg}, are already extremely accurate at the CC3 level, and systematically improved by CCSDT and CC4. Finally, for the CC models (Table \ref{tab:D2h}), the two states with a large $\%T_1$ value, {\tBoneg} and {\sBoneg}, are already extremely accurate at the CC3 level, and systematically improved by CCSDT and CC4.
This trend is in line with the observations made on the QUEST database. \cite{Veril_2021} This trend is in line with the observations made on the QUEST database. \cite{Veril_2021}
For the doubly-excited state, {\twoAg}, the convergence of the CC expansion is much slower but it is worth pointing out that the inclusion of approximate quadruples via CC4 is particularly effective, in line with an earlier work. \cite{Loos_2021} For the doubly-excited state, {\twoAg}, the convergence of the CC expansion is much slower but it is worth pointing out that the inclusion of approximate quadruples via CC4 is particularly effective, as observed in an earlier work. \cite{Loos_2021}
The CCSDTQ excitation energies (which are used to define the TBEs) are systematically within the error bar of the CIPSI extrapolations, which confirms the outstanding performance of CC methods that include quadruple excitations in the context of excited states. The CCSDTQ excitation energies (which are used to define the TBEs) are systematically within the error bar of the CIPSI extrapolations, which confirms the outstanding performance of CC methods that include quadruple excitations in the context of excited states.
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