diff --git a/SlideToulouse/main.tex b/SlideToulouse/main.tex index 8d2d62e..d0f3154 100644 --- a/SlideToulouse/main.tex +++ b/SlideToulouse/main.tex @@ -8,19 +8,19 @@ \usepackage[english]{babel} \usepackage[T1]{fontenc} \usepackage[utf8]{inputenc} +\usepackage{xcolor} \usepackage{siunitx} \usepackage{graphicx} \usepackage{physics} \usepackage{multimedia} \usepackage{subfigure} -\usepackage{xcolor} \usepackage[absolute,overlay]{textpos} \usepackage{ragged2e} \usepackage{amssymb} \usepackage[version=4]{mhchem} -\renewcommand{\thefootnote}{\alph{footnote}} + %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% @@ -61,9 +61,8 @@ \beamerboxesdeclarecolorscheme{clair}{Coral4}{Ivory2} \beamerboxesdeclarecolorscheme{foncé}{DarkSeaGreen4}{Ivory2} -\title[Title]{Perturbative theories in the complex plane} +\title[Title]{Perturbation theories in the complex plane} \author[]{Antoine \textsc{Marie}} -\date{30 Juin 2020} \setbeamersize{text margin left=5mm} \setbeamersize{text margin right=5mm} \institute{Supervised by Pierre-François \textsc{LOOS}} @@ -71,21 +70,50 @@ \begin{document} + + %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \begin{frame}[plain] -\date{24 Avril 2020} +\date{30th June 2020} \titlepage \end{frame} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\begin{frame}{Why do we use perturbation theories in computational chemistry?} + +\pause[1] + +The Hartree-Fock theory is \textcolor{Green4}{computationally cheap} and can be applied even to \textcolor{Green4}{large systems}. + +But this method is missing the \textcolor{red}{correlation energy}... + +\vspace{0.5cm} + +\pause[2] + +$\rightarrow$ We need methods to get this correlation energy! + +\vspace{0.5cm} + +\pause[3] + +\begin{beamerboxesrounded}[scheme=foncé]{\centering A general method} +In physics perturbation theory is often a good way to improve the obtained results with an approximated Hamiltonian. +\end{beamerboxesrounded} + + +\end{frame} + \section{\textsc{Strange behaviors of the MP series}} -\begin{frame}{The Möller-Plesset theory} +\begin{frame}{The Møller-Plesset perturbation theory} + +\pause[1] \begin{beamerboxesrounded}[scheme=foncé]{\centering Partitioning of the Hamiltonian} @@ -97,23 +125,33 @@ \begin{itemize} \centering - \item $H_0$ : Unperturbed Hamiltonian - \item $V$ : Perturbation operator + \item $H_0$: Unperturbed Hamiltonian + \item $V$: Perturbation operator \end{itemize} +\pause[2] + \begin{beamerboxesrounded}[scheme=foncé]{\centering The Fock operator} \begin{equation} F = T + J + K \end{equation} + \end{beamerboxesrounded} \begin{itemize} \centering - \item $T$ : Kinetic energy operator - \item $J$ : Coulomb operator - \item $K$ : Exchange operator + \item $T$: Kinetic energy operator + \item $J$: Coulomb operator + \item $K$: Exchange operator \end{itemize} + +\pause[3] + +\begin{beamerboxesrounded}[scheme=foncé]{} +\centering +Full Configuration Interaction gives us access to high order terms of the perturbation series ! +\end{beamerboxesrounded} \end{frame} @@ -121,12 +159,11 @@ \begin{figure} \centering - \includegraphics[width=0.5\textwidth]{gill1986.png} - \caption{\centering Barriers to homolytic fission of \ce{He2^2+} using minimal basis set MPn theory (n~=~1-20).} + \includegraphics[width=0.4\textwidth]{gill1986.png} + \caption{\centering Barriers to homolytic fission of \ce{He2^2+} using STO-3G basis set MPn theory (n~=~1-20).} \label{fig:my_label} \end{figure} -\footnotetext{\tiny{Gill et al.~Deceptive convergence in Møller-Plesset perturbation energies, \textit{Chemical Physics Letter}, 1986}} \end{frame} @@ -135,7 +172,7 @@ \centering \begin{tabular}{c c c c c c c} \hline - $r$ & UHF & UMP2 & UMP3 & UMP4 & $$ \\ + $r$ & UHF & UMP2 & UMP3 & UMP4 & $\expval{S^2}$ \\ \hline 0.75 & 0.0\% & 63.8\% & 87.4\% & 95.9\% & 0.00\\ 1.35 & 0.0\% & 15.2\% & 26.1\% & 34.9\% & 0.49\\ @@ -143,7 +180,7 @@ 2.50 & 0.0\% & 00.1\% & 00.3\% & 00.4\% & 0.99\\ \hline \end{tabular} - \caption{\centering Percentage of electron correlation energy recovered and $$ for the \ce{H2} molecule as a function of bond length (r,A) in the minimal basis.} + \caption{\centering Percentage of electron correlation energy recovered and $\expval{S^2}$ for the \ce{H2} molecule as a function of bond length (r,\si{\angstrom}) in the STO-3G basis set.} \label{tab:my_label} \end{table} @@ -199,7 +236,7 @@ \end{columns} -But the Taylor expansion of this function does not converge for $x\geq1$ ... +But the Taylor expansion of this function does not converge for $x\geq1$... \vspace{0.3cm} \centering Why ? @@ -217,8 +254,6 @@ But the Taylor expansion of this function does not converge for $x\geq1$ ... $x = e^{i\pi/4}, e^{-i\pi/4}, e^{i3\pi/4}, e^{-i3\pi/4}$ - - \column{0.48\textwidth} \begin{figure} @@ -239,7 +274,7 @@ The \textcolor{red}{radius of convergence} of the Taylor expansion of a function \begin{beamerboxesrounded}[scheme=foncé]{\centering $\lambda$ a complex variable} \begin{equation*} - H = H_0 + \lambda V + H(\lambda) = H_0 + \lambda V \end{equation*} \end{beamerboxesrounded} @@ -273,7 +308,7 @@ The \textcolor{red}{radius of convergence} of the Taylor expansion of a function \begin{frame}{Which features of the system localize the singularities ?} \begin{itemize} - \item Partitioning of the Hamiltonian: Möller-Plesset, Epstein-Nesbet, ... + \item Partitioning of the Hamiltonian: Møller-Plesset, Epstein-Nesbet,... \item Zeroth order reference: weak correlation or strongly correlated electrons. \item Finite or complete basis set. \item Localized or delocalized basis functions. @@ -296,27 +331,12 @@ The \textcolor{red}{radius of convergence} of the Taylor expansion of a function \column{0.48\textwidth} -\begin{beamerboxesrounded}[scheme=foncé]{A 2x2 matrix\textsuperscript{a}} +\begin{beamerboxesrounded}[scheme=foncé]{A 2x2 matrix} +\centering \small{$\mqty(\alpha & \delta \\ \delta & \beta) =$} -$ +\vspace{0.15cm} -\small{\centering \begin{pmatrix} - \alpha & \delta \\ - \delta & \beta -\end{pmatrix} = - -\vspace{0.3cm} - -\begin{pmatrix} - - \alpha + \alpha_s & 0 \\ - 0 & \beta + \beta_s -\end{pmatrix} + -\begin{pmatrix} - - \alpha_s & \delta \\ - \delta & - \beta_s -\end{pmatrix}} -$ +\small{$\mqty(\alpha + \alpha_s & 0 \\ 0 & \beta + \beta_s ) + \mqty(- \alpha_s & \delta \\ \delta & - \beta_s)$} \end{beamerboxesrounded} \vspace{1cm} @@ -326,7 +346,7 @@ $ \end{frame} -\begin{frame}{Two state model} +\begin{frame}{Two-state model} \begin{figure} \centering @@ -341,57 +361,91 @@ $ \begin{frame}{Existence of a critical point} -For $\lambda<0$ : +For $\lambda<0$: \begin{equation*} - H(\lambda)=\sum\limits_{j=1}^{2n}\left[ \underbrace{-\frac{1}{2}\nabla_j^2 - \sum\limits_{k=1}^{N} \frac{Z_k}{|\vb{r}_j-\vb{R}_k|}}_{\text{Independant of }\lambda} + \overbrace{(1-\lambda)V_j^{(scf)}}^{\textcolor{red}{Repulsive}}+\underbrace{\lambda\sum\limits_{j