new color schemes and corrections

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Antoine Marie 2023-03-09 15:32:50 +01:00
parent 006cae7f2e
commit c505ee41c4
6 changed files with 8 additions and 7 deletions

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@ -626,12 +626,13 @@ The convergence properties and the accuracy of both static approximations are qu
To conclude this section, we briefly discussed the case of discontinuities mentioned in Sec.~\ref{sec:intro}.
Indeed, it has been previously mentioned that intruder states are responsible for both the poor convergence of qs$GW$ and discontinuities in physical quantities. \cite{Loos_2018b,Veril_2018,Loos_2020e,Berger_2021,DiSabatino_2021,Monino_2022,Scott_2023}
Is it then possible to rely on the SRG machinery to remove discontinuities?
Not directly because discontinuities are due to intruder states in the dynamic part of the quasiparticle equation, while, as we have seen just above, a \titou{finite} value of $s$ is suitable to avoid intruder states in its static part.
However, performing a bijective transformation of the form,
Not directly because discontinuities are due to intruder states in the dynamic part of the quasiparticle equation.
However, as we have seen just above the functional form of the renormalized equation \ant{makes it possible to choose $s$ such that there is no intruder states in its static part.}
But performing a bijective transformation of the form,
\begin{align}
e^{- \Delta s} &= 1-e^{-\Delta t},
\end{align}
on the renormalized quasiparticle equation \eqref{eq:GW_renorm} reverses the situation and makes \titou{finite} values of $t$ suitable to avoid discontinuities in the regularized dynamic part of the quasiparticle equation.
\end{align}
on the renormalized quasiparticle equation \eqref{eq:GW_renorm} reverses the situation and \ant{makes it possible to choose $t$ such that there is no intruder states in the dynamic part, hence removing discontinuities.}
Note that, after this transformation, the form of the regularizer is actually closely related to the SRG-inspired regularizer introduced by Monino and Loos in Ref.~\onlinecite{Monino_2022}.
%=================================================================%
@ -652,7 +653,7 @@ We use (restricted) HF guess orbitals and energies for all self-consistent $GW$
The maximum size of the DIIS space \cite{Pulay_1980,Pulay_1982} and the maximum number of iterations were set to 5 and 64, respectively.
In practice, one may achieve convergence, in some cases, by adjusting these parameters or by using an alternative mixing scheme.
However, in order to perform black-box comparisons, these parameters have been fixed to these default values.
The $\eta$ value has been set to \num{e-3} for the conventional $G_0W_0$ calculations \titou{where we have not linearized the quasiparticle equation} while, for the qs$GW$ calculations, $\eta$ has been chosen as the largest value where one successfully converges the 50 systems composing the test set.
The $\eta$ value has been set to \num{e-3} for the conventional $G_0W_0$ \ant{(without linearization of the quasiparticle equation)} calculations while, for the qs$GW$ calculations, $\eta$ has been chosen as the largest value where one successfully converges the 50 systems composing the test set.
The various $GW$-based sets of values are compared with a set of reference values computed at the $\Delta$CCSD(T) level with the same basis set.
The $\Delta$CCSD(T) principal ionization potentials (IPs) and electron affinities (EAs) have been obtained using \textsc{gaussian 16} \cite{g16} with default parameters within the restricted and unrestricted HF formalism for the neutral and charged species, respectively.
@ -770,7 +771,7 @@ Table \ref{tab:tab1} shows the principal IP of the 50 molecules considered in th
As mentioned previously the HF approximation overestimates the IPs with a mean signed error (MSE) of \SI{0.56}{\eV} and a mean absolute error (MAE) of \SI{0.69}{\eV}.
Performing a one-shot $G_0W_0$ calculation on top of this mean-field starting point, $G_0W_0$@HF, reduces by more than a factor two the MSE and MAE, \SI{0.29}{\eV} and \SI{0.33}{\eV}, respectively.
However, there are still outliers with large errors.
\titou{For example, the IP of \ce{N2} is overestimated by \SI{1.56}{\eV}.}
\ant{For example, the IP of \ce{N2} is overestimated by \SI{1.56}{\eV}, a large error which is clearly due to the starting point dependence of $G_0W_0$@HF.}
Self-consistency can mitigate the error of the outliers as the MAE at the qs$GW$ level is now \SI{0.57}{\eV} and the standard deviation of the error (SDE) is decreased from \SI{0.31}{\eV} for $G_0W_0$ to \SI{0.18}{\eV}.
In addition, the MSE and MAE (\SI{0.23}{\eV} and \SI{0.25}{\eV}, respectively) are also slightly improved with respect to $G_0W_0$@HF.
@ -869,7 +870,7 @@ Indeed, up to $s=\num{e3}$ SRG-qs$GW$ self-consistency can be attained without a
For $s=\num{5e3}$, convergence could not be attained for 11 molecules out of 50.
This means that some intruder states were included in the static correction for this value of $s$.
However, this is not a problem as the MAE of the test set is already well converged at $s=\num{e3}$.
This is illustrated by the blue curve of Fig.~\ref{fig:fig6} which shows the evolution of the MAE with respect to $s$ and \titou{$\eta=1/2s^2$}.
This is illustrated by the blue curve of Fig.~\ref{fig:fig6} which shows the evolution of the MAE with respect to $s$ and $s=1/2\eta^2$.
The convergence plateau of the MAE is reached around $s=50$ while the convergence problem arises for $s>\num{e3}$.
Therefore, for future studies using the SRG-qs$GW$ method, a default value of the flow parameter equal to $\num{5e2}$ or $\num{e3}$ is recommended.

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