\documentclass[10pt]{letter}
\usepackage{UPS_letterhead,xcolor,mhchem,mathpazo,ragged2e}
\newcommand{\alert}[1]{\textcolor{red}{#1}}
\definecolor{darkgreen}{HTML}{009900}


\begin{document}

\begin{letter}%
{To the Editors of the Journal of Chemical Physics}

\opening{Dear Editors,}

\justifying
Please find enclosed our manuscript entitled
\begin{quote}
\textit{``A weight-dependent local correlation density-functional approximation for ensembles''}, 
\end{quote}
which we would like you to consider as a Regular Article in the \textit{Journal of Chemical Physics}.
This contribution fits nicely in the section \textit{``Theoretical Methods and Algorithms''}. 
This contribution has never been submitted in total nor in parts to any other journal, and has been seen and approved by all authors.

To the best of our knowledge, the present article reports, for the first
time, a local \textit{weight-dependent} correlation density-functional
approximation that incorporates information about both ground and excited states in the context of density-functional theory for ensembles (eDFT). 
This density-functional approximation for ensembles is specially
designed for the computation of single and double excitations within
Gross-Oliveira-Kohn (GOK) DFT (i.e., eDFT for neutral excitations), and can be seen as a natural extension of the ubiquitous local-density approximation in the case of ensembles.
We show that the present weight-dependent correlation functional delivers accurate excitation energies for both single and double excitations in one-dimensional non-homogeneous many-electron systems.
Comparison with TD-DFT shows that the present methodology is not only robust in the weakly-correlated regime, but also in presence of strong correlation where TD-DFT fails.
Although the present weight-dependent functional has been specifically
designed for one-dimensional systems, the methodology proposed here is
general, {\it i.e.}, directly applicable to the construction of weight-dependent functionals for realistic three-dimensional systems, such as molecules and solids.

Because of the large impact of our work in the DFT community and beyond, we expect it to be of interest to a wide audience within the chemistry and physics communities.
We suggest Tim Gould, Stefano Pittalis, Leeor Kronik, Julien Toulouse, Evert Baerends, Trygve Helgaker, Paola Gori-Giorgi, and Aurora Pribram-Jones as potential referees.
We look forward to hearing from you soon.

\closing{Sincerely, the authors.}


\end{letter}
\end{document}






