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Pierre-Francois Loos 2019-05-25 00:00:32 +02:00
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@ -174,8 +174,17 @@ By combining extrapolated selected configuration interaction (sCI) calculations
\label{sec:intro} \label{sec:intro}
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One of the most fundamental problem of conventional electronic structure methods is their slow energy convergence with respect to the size of the one-electron basis set. One of the most fundamental problem of conventional electronic structure methods is their slow energy convergence with respect to the size of the one-electron basis set.
Explicitly-correlated F12 methods have been specifically designed to cure this problem.
Although they have extremely successful to speed up convergence of the ground state properties such as correlation and atomization energies (for example), their performances for excited states have been much more conflicting.
In the present study, we rely on the recently proposed short-range density-functional functional correction for basis set incompleteness. \cite{GinPraFerAssSavTou-JCP-18} There are two types of basis set completeness: angular and radial completeness.
F12 is good at doing angular basis set correction.
However, radial correction are much harder to design and it is a real test for the present approach.
Instead of F12 methods, here we propose to follow a different philosophy and rely on the recently proposed short-range density-functional functional correction to reduce the basis set incompleteness error. \cite{GinPraFerAssSavTou-JCP-18}
This choice is motivated by the much faster convergence of these methods with respect to the size of the basis set. \cite{FraMusLupTou-JCP-15}
The present method is illustrated on several molecules and singly- and doubly-excited states with diffuse basis sets.
%Contemporary quantum chemistry has developed in two directions --- wave function theory (WFT) \cite{Pop-RMP-99} and density-functional theory (DFT). \cite{Koh-RMP-99} %Contemporary quantum chemistry has developed in two directions --- wave function theory (WFT) \cite{Pop-RMP-99} and density-functional theory (DFT). \cite{Koh-RMP-99}
%Although both spring from the same Schr\"odinger equation, each of these philosophies has its own \textit{pros} and \textit{cons}. %Although both spring from the same Schr\"odinger equation, each of these philosophies has its own \textit{pros} and \textit{cons}.