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+\documentclass[10pt]{letter}
+\usepackage{UPS_letterhead,color,mhchem,mathpazo,ragged2e}
+\newcommand{\alert}[1]{\textcolor{red}{#1}}
+
+\begin{document}
+
+\begin{letter}%
+{To the Editors of the The Journal of Physical Chemistry Letters}
+
+\opening{Dear Editors,}
+
+\justifying
+Please find enclosed our manuscript entitled \textit{``Hierarchy Configuration Interaction: Combining Seniority Number and Excitation Degree''}, 
+which we would like you to consider as a Letter to the \textit{Journal of Physical Chemistry Letters}.
+This contribution nicely fits in the \textit{``Physical Insights into Quantum Phenomena and Function''} subject category.
+This contribution has never been submitted in total nor in parts to any other journal, and has been seen and approved by all authors.
+
+Several quantum chemistry methodologies, including single- and multi-reference configuration interaction (CI) and coupled cluster, 
+rely on an educated truncation of the full Hilbert space, while trying to keep most of its relevant physics.
+From the birth of quantum chemistry and for many decades, most methods have been developed under an \textit{excitation}-based framework,
+which are usually successful in weak-correlation regimes, and, importantly, present favourable (polynomial) computational scaling.
+Over the past ten years, there has been a growing interest in \textit{seniority}-based methods,
+which are more suitable for strong-correlation regimes, even though they display a much steeper (exponential) computational scaling.
+
+Aiming at recovering the best of both worlds, here we present a novel partitioning of the Hilbert space, \textit{hierarchy} configuration interaction (hCI).
+By benchmarking hCI against its excitation- and seniority-based parents and numerically exact results, for a series of challenging molecular systems,
+and for several relevant properties, we demonstrate its overall superior convergence.
+hCI inherits both the quick recovery of weak correlation and the favourable computational cost from excitation-based CI,
+as well as a better account of strong correlation from seniority-based CI.
+
+Based on the robust performance and appealing features of hCI, we expect our proposed strategy will both inspire further developments within the electronic structure community
+and foment exploratory applications to chemically relevant systems.
+Because of its novelty and impact, we expect the present study to be of interest to a wide audience within the chemistry and physics communities.
+We suggest A, B, C as potential referees.
+
+We look forward to hearing from you soon.
+
+\closing{Sincerely,}
+
+
+\end{letter}
+\end{document}
diff --git a/Manuscript/Cover_Letter/UPS_letterhead.sty b/Manuscript/Cover_Letter/UPS_letterhead.sty
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+++ b/Manuscript/Cover_Letter/UPS_letterhead.sty
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+%ANU etterhead Yves
+%version 1.0	12/06/08
+%need to be improved
+
+
+\RequirePackage{graphicx}
+
+%%%%%%%%%%%%%%%%%%%%% DEFINE USER-SPECIFIC MACROS BELOW %%%%%%%%%%%%%%%%%%%%%
+\def\Who     {Pierre-Fran\c{c}ois Loos}
+\def\What    {Dr}
+\def\Where   {Universit\'e Paul Sabatier}
+\def\Address {Laboratoire de Chimie et Physique Quantiques}
+\def\CityZip {Toulouse, France}
+\def\Email   {loos@irsamc.ups-tlse.fr}
+\def\TEL     {+33 5 61 55 73 39}
+\def\URL     {} % NOTE: use $\sim$ for tilde
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% MARGINS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\textwidth       6in
+\textheight      9.25in
+\oddsidemargin   0.25in
+\evensidemargin  0.25in
+\topmargin       -1.50in
+\longindentation 0.50\textwidth
+\parindent       5ex
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%% ADDRESS MACRO BELOW %%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+\address{
+    \includegraphics[height=0.7in]{CNRS_logo.pdf}     \hspace*{\fill}\includegraphics[height=0.7in]{UPS_logo.pdf}
+	\\
+	\hrulefill
+	\\
+	{\small \What~\Who\hspace*{\fill} Telephone:\ \TEL
+	\\
+	\Where\hspace*{\fill}  Email:\ \Email
+	\\
+	\Address\hspace*{\fill}
+	\\
+	\CityZip\hspace*{\fill} \URL}
+	 }
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%% OTHER MACROS BELOW %%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\signature{\What~\Who}
+
+\def\opening#1{\ifx\@empty\fromaddress
+ \thispagestyle{firstpage}
+ \hspace*{\longindendation}\today\par
+ \else \thispagestyle{empty}
+ {\centering\fromaddress \vspace{5\parskip} \\
+\today\hspace*{\fill}\par}
+ \fi
+ \vspace{3\parskip}
+ {\raggedright \toname \\ \toaddress \par}\vspace{3\parskip}
+ \noindent #1\par\raggedright\parindent 5ex\par
+ }
+
+%I do not know what does the macro below
+
+%\long\def\closing#1{\par\nobreak\vspace{\parskip}
+ %\stopbreaks
+ %\noindent
+ %\ifx\@empty\fromaddress\else
+ %\hspace*{\longindentation}\fi
+ %\parbox{\indentedwidth}{\raggedright
+ %\ignorespaces #1\vskip .65in
+ %\ifx\@empty\fromsig
+ %\else \fromsig \fi\strut}
+ %\vspace*{\fill}
+% \par}
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