Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

applying suggested changes #16

Open
wants to merge 7 commits into
base: main
Choose a base branch
from
Open
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Binary file added theory/presentation/figures/cuhf_mix.pdf
Binary file not shown.
Binary file added theory/presentation/figures/h3_cis copy 2.png
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Binary file added theory/presentation/figures/h3_cis.pdf
Binary file not shown.
Binary file modified theory/presentation/figures/h3_cis.png
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Binary file added theory/presentation/figures/h3_cis_copy.png
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Binary file added theory/presentation/figures/h3_cuhf.pdf
Binary file not shown.
Binary file added theory/presentation/figures/h3_uhf_sto-3g.pdf
Binary file not shown.
Binary file added theory/presentation/figures/rhf.pdf
Binary file not shown.
Binary file added theory/presentation/figures/uhf.pdf
Binary file not shown.
Empty file.
196 changes: 115 additions & 81 deletions theory/presentation/presentation.tex
Original file line number Diff line number Diff line change
Expand Up @@ -48,66 +48,74 @@
% I guess you always want a titleframe
\titleframe

% Have this if you'd like a frame containing the
% table of content
\begin{frame}{Overview}
\tableofcontents[hideallsubsections]
\end{frame}

% Start of the first section
\section{Introduction}

\begin{frame}
\frametitle{The Hartree-Fock approximation}
The Schrödinger equation
\begin{equation}
\hat{H}\Psi = E\Psi
\end{equation}
The Roothaan-Hall equation
\begin{equation}
\mathbf{FC} = \epsilon \mathbf{SC}
\end{equation}
One constraint $\Longrightarrow$ energy minimum
\begin{equation}
\hat{f} = \hat{h}(1) + \sum_j^N\hat{J}_j - \hat{K}_j
\end{equation}
\begin{equation}
\langle \psi + \delta\psi | \hat{H} | \psi + \delta\psi \rangle = E + \delta E^* + \delta E + \delta E^2
\langle \psi + \delta\psi | \hat{H} | \psi + \delta\psi \rangle = E + \delta E^* + \delta E + \delta E^2 = E
\end{equation}

\end{frame}

\begin{frame}
\frametitle{Löwdin's symmetry dilema}
\frametitle{Restricted Hartree-Fock}
\begin{itemize}
\item Restricted Hartree-Fock
\begin{itemize}
\item Higher energy
\item Symmetry intact
\end{itemize}
\item Unrestricted Hartree-Fock
\begin{itemize}
\item Lower energy
\item Spin quantum numbers lost
\end{itemize}
\item Electrons forced into pairs
\item Higher energy
\item Symmetry intact
\end{itemize}
\begin{minipage}[b]{0.6\linewidth}
\includegraphics[width=\linewidth]{./figures/rhf.pdf}
\end{minipage}

\end{frame}


\begin{frame}
\frametitle{Unrestricted Hartree-Fock}
\begin{itemize}
\item No electron pairs
\item Lower energy
\item $\langle\hat{S}^2\rangle$ lost as quantum number
\end{itemize}
\begin{minipage}[b]{0.6\linewidth}
\includegraphics[width=\linewidth]{./figures/uhf.pdf}
\end{minipage}
\begin{minipage}[b]{0.35\linewidth}
\begin{equation}
\delta s = \langle \hat{S}^2 \rangle - S_z(S_z + 1)
\end{equation}
\end{minipage}
\end{frame}


\begin{frame}
\frametitle{Spin contamination}
\begin{equation}
\langle \hat{S}^2 \rangle = S_z^2 + S_z + q - \sum_{ij}^{pq}S_{ij}^2
\end{equation}
\frametitle{Löwdin's symmetry dillema}
\begin{itemize}
\item Low energy $\Longrightarrow$ loss of symmetry
\item Keeping symmetry $\Longrightarrow$ high symmetry
\item Do we always lose?
\end{itemize}

\begin{equation}
\delta s = \langle \hat{S}^2 \rangle - S_z(S_z + 1)
\end{equation}

\begin{figure}
\begin{minipage}[b]{0.45\linewidth}
\includegraphics[width=\linewidth]{./figures/rhf.png}
\end{minipage}
\begin{minipage}[b]{0.45\linewidth}
\includegraphics[width=\linewidth]{./figures/uhf.png}
\end{minipage}
\end{figure}

\begin{itemize}
\item Can we keep both symmetry and lower energies?
\begin{itemize}
\item ROHF
\item CUHF
\end{itemize}
\end{itemize}

\end{frame}

Expand All @@ -133,14 +141,14 @@ \section{Theory}

\begin{frame}
\begin{figure}
\includegraphics[width=0.6\linewidth]{./figures/cuhf_mix.png}
\includegraphics[width=0.6\linewidth]{./figures/cuhf_mix.pdf}
\end{figure}
\end{frame}

\begin{frame}
\frametitle{Configuration interaction}
\frametitle{Configuration interaction: CIS}
\begin{equation}\label{eq:lincomb}
|\Psi_0\rangle = c_0|\Phi_0\rangle + \sum_{ar}c_{r}^{a}|\Phi_r^a\rangle + \sum_{a<b,r<s}c_{rs}^{ab}|\Phi^{ab}_{rs} \rangle + \cdots
|\Psi_0\rangle = {\color{ugent-re} c_0|\Phi_0\rangle + \sum_{ar}c_{r}^{a}|\Phi_r^a\rangle} + \sum_{a<b,r<s}c_{rs}^{ab}|\Phi^{ab}_{rs} \rangle + \cdots
\end{equation}
Brillouin's theorem:
\begin{equation}\label{eq:overlapsingle}
Expand All @@ -154,14 +162,31 @@ \section{Theory}

\section{results}

\begin{frame}
\frametitle{Goals}
\begin{enumerate}
\item Excitation energy levels
\item Differences/similarities between methods
\begin{itemize}
\item UHF
\item CUHF
\item ROHF
\end{itemize}
\item Spin contamination in the excited states
\end{enumerate}



\end{frame}

\begin{frame}
\frametitle{\ce{H3}}
\begin{figure}
\begin{minipage}[b]{0.45\linewidth}
\includegraphics[width=\linewidth]{./figures/h3_uhf_sto-3g.png}
\includegraphics[width=\linewidth]{./figures/h3_uhf_sto-3g.pdf}
\end{minipage}
\begin{minipage}[b]{0.45\linewidth}
\includegraphics[width=\linewidth]{./figures/h3_cuhf.png}
\includegraphics[width=\linewidth]{./figures/h3_cuhf.pdf}
\end{minipage}
\end{figure}

Expand All @@ -171,7 +196,7 @@ \section{results}
\begin{frame}
\frametitle{CUHF and UHF}
\begin{minipage}[b]{0.6\linewidth}
\includegraphics[width=\linewidth]{./figures/h3_cis.png}
\includegraphics[width=\linewidth]{./figures/h3_cis.pdf}
\end{minipage}
\begin{minipage}[b]{0.3\linewidth}
\begin{table}[h]
Expand All @@ -180,8 +205,8 @@ \section{results}
& UHF & CUHF \\
\hline
1 & -2.938139 & -2.922658 \\
2 & -2.923512 & -2.915707 \\
3 & -2.896022 & -2.915707 \\
2 & {\color{ugent-re} \textbf{-2.923512}} & {\color{ugent-re} \textbf{-2.915707}} \\
3 & -2.896022 & {\color{ugent-re} \textbf{-2.915707}} \\
4 & -2.840079 & -2.895707 \\
5 & -2.560947 & -2.560947 \\
6 & -2.428072 & -2.436524 \\
Expand All @@ -192,41 +217,12 @@ \section{results}
\end{tabular}
\end{table}
\end{minipage}
\begin{itemize}
\item degeneracies
\item lower energy states
\end{itemize}
\end{frame}

\begin{frame}
\begin{figure}[h]
\begin{center}
\begin{tikzpicture}
\draw (-1.25, 0.5) -- (-0.75, 0.5);
\draw (-1.25, 0) -- (-0.75, 0);
\draw (-1.25, -0.5) -- (-0.75, -0.5);
\draw [-{Straight Barb[left]}] (-1.1, -0.60) -- (-1.1, -0.20);
\draw [-{Straight Barb[left]}] (-1.1, -0.10) -- (-1.1, 0.30);
\draw [-{Straight Barb[left]}] (-0.9, -0.20) -- (-0.9, -0.60);

\draw (1.25, 0.5) -- (0.75, 0.5);
\draw (1.25, 0) -- (0.75, 0);
\draw (1.25, -0.5) -- (0.75, -0.5);
\draw [-{Straight Barb[left]}] (0.9, -0.60) -- (0.9, -0.20);
\draw [-{Straight Barb[left]}] (1.1, 0.30) -- (1.1, -0.10);
\draw [-{Straight Barb[left]}] (1.1, -0.20) -- (1.1, -0.60);
\end{tikzpicture}
\end{center}
\end{figure}
\begin{table}[h]
\label{tab:excits_no_triplets}
\begin{tabular}{l|l|l}
& UHF & CUHF \\
\hline
1 & -2.923515 & -2.915707 \\
2 & -2.840101 & -2.895707 \\
3 & -2.428086 & -2.436524 \\
4 & -2.160319 & -2.176620 \\
5 & -2.137039 & -2.139049
\end{tabular}
\end{table}
\end{frame}
\begin{frame}
\frametitle{CUHF and ROHF}

Expand Down Expand Up @@ -265,16 +261,19 @@ \section{results}
\end{frame}
\section{Conclusions and prospects}
\begin{frame}
\frametitle{Conclusions and prospects}
\begin{itemize}
\item Things to look out for:
\item CUHF takes care of spin contamination in the ground state
\item Things to look out for in CIS
\begin{itemize}
\item triplet excitations with lower energy
\item triplet excitations with lower energy (for some systems)
\item spin contamination
\end{itemize}
\item Prospects
\begin{itemize}
\item triplet systems
\item Full CI $\Longrightarrow$ other constraints?
\item Higher order CI
\item Other constraints $\Longrightarrow$ excited states?
\end{itemize}
\end{itemize}

Expand All @@ -283,4 +282,39 @@ \section{Conclusions and prospects}
% End presentation with titleframe
\titleframe

\begin{frame}
\begin{figure}[h]
\begin{center}
\begin{tikzpicture}
\draw (-1.25, 0.5) -- (-0.75, 0.5);
\draw (-1.25, 0) -- (-0.75, 0);
\draw (-1.25, -0.5) -- (-0.75, -0.5);
\draw [-{Straight Barb[left]}] (-1.1, -0.60) -- (-1.1, -0.20);
\draw [-{Straight Barb[left]}] (-1.1, -0.10) -- (-1.1, 0.30);
\draw [-{Straight Barb[left]}] (-0.9, -0.20) -- (-0.9, -0.60);

\draw (1.25, 0.5) -- (0.75, 0.5);
\draw (1.25, 0) -- (0.75, 0);
\draw (1.25, -0.5) -- (0.75, -0.5);
\draw [-{Straight Barb[left]}] (0.9, -0.60) -- (0.9, -0.20);
\draw [-{Straight Barb[left]}] (1.1, 0.30) -- (1.1, -0.10);
\draw [-{Straight Barb[left]}] (1.1, -0.20) -- (1.1, -0.60);
\end{tikzpicture}
\end{center}
\end{figure}
$\Longrightarrow$ The ground state is degenerate
\begin{table}[h]
\label{tab:excits_no_triplets}
\begin{tabular}{l|l|l}
& UHF & CUHF \\
\hline
1 & {\color{ugent-re} \textbf{-2.923512}} & {\color{ugent-re} \textbf{-2.915707}} \\
2 & -2.840101 & -2.895707 \\
3 & -2.428086 & -2.436524 \\
4 & -2.160319 & -2.176620 \\
5 & -2.137039 & -2.139049
\end{tabular}
\end{table}
\end{frame}

\end{document}