# diagram low spin vs high spin (modiagram)

I am working on my thesis and I want to draw a figure that gives a comparison of electron distribution in iron(II) between LS and HS state. It should look like the picture below. I made several attempts with modiagram, but I am not able to align the orbitals horizontally. I don't know how I can complete the missing part of the figure (right side)

Here is what I have:

\documentclass{article}
\usepackage{modiagram}
\usepackage{upgreek}
\begin{document}

\begin{figure}
\centering
\begin{MOdiagram}[lines = gray]
\small
% Metal
\AO[metal-3d-1]{s}{-0.10;}
\AO[metal-3d-2]{s}{-0.05;}
\AO[metal-3d-3]{s}{ 0.00;}
\AO[metal-3d-4]{s}{ 0.05;}
\AO[metal-3d-5]{s}{ 0.10;}
% Complex
\AO[complex-t2g-1](50 pt){s}{-1.05;}
\AO[complex-t2g-2](50 pt){s}{-1.00;}
\AO[complex-t2g-3](50 pt){s}{-0.95;}
\AO[complex-eg-1] (50 pt){s}{1.50;}
\AO[complex-eg-2] (50 pt){s}{1.55;}

\node[inner sep = 0, outer sep = 0]
(midway) at (55 pt, 0 pt) {};
\draw[style = dotted] (45 pt, 0 pt) --  ++ (10 pt, 0 pt);

\connect{
metal-3d-3 & complex-t2g-2,
metal-3d-3 & complex-eg-1
}
\node[right] at (complex-t2g-1.east){$\mathrm{t}_{2\mathrm{g}}$};
\node[right] at (complex-eg-1.east) {$\mathrm{e}_{\mathrm{g}}$};

\draw[orange, <->] (complex-t2g-3.west) -- (complex-eg-1.west)
node[midway,left] {$\Delta_{\mathrm{O}}$} ;
\draw[orange, <->] (complex-eg-1.east) -- (midway.east)
node[midway,right] {$\frac{3}{5}\Delta_{\mathrm{O}}$} ;
\draw[orange, <->] (complex-t2g-3.east) -- (midway.east)
node[midway,right] {$\frac{2}{5}\Delta_{\mathrm{O}}$} ;
\EnergyAxis[title]
\end{MOdiagram}
\caption{Octahedral field splitting}
\end{figure}

\end{document}

• It is probably easier to just draw this with TikZ directly… Mar 2 '17 at 18:24

A solution with tikz. Its only a start and not 100% equal to your example. Modifications will help to get your style. Add \usetikzlibrary{arrows.meta} and \usepackage[eulergreek]{sansmath}.

Manual(...,16.5.4 Caps)

MWE:

\documentclass[border=2mm]{standalone}
%\usepackage{tikz}
\usepackage{graphicx}
\usepackage{pgfplots}
\pgfplotsset{compat=1.14}
%\pagestyle{empty}
\usetikzlibrary{arrows.meta}
\usepackage[eulergreek]{sansmath}

\begin{document}
\begin{tikzpicture}[>=latex,font=\sffamily\sansmath]
\begin{axis}[
axis line style = ultra thick,
axis x line=center,
axis y line=center,
xtick=\empty,%{-5,-4,...,5},
ytick=\empty,%{-5,-4,...,5},
xlabel={\textbf{Ligandenfeldstärke}},
ylabel={\textbf{Energie}},
x label style={at={(axis description cs:0.5,0)},anchor=north},
y label style={at={(axis description cs:0,.5)},rotate=90,anchor=south},
xmin=0,
xmax=20,
ymin=0,
ymax=20,
y=0.32cm,
x=0.6cm,]
\end{axis}
\foreach \a in {3,+3.1,...,3.5} {
\draw[black,thick] (0.2,\a) -- (1.0,\a);
};
\node at (0.6,3.6) {$d_6$};

\draw[thick] (1.2,3.2) -- (3.2,5) node[anchor=west] {$e_g$};
\draw[thick] (1.2,3.2) -- (3.2,1.4) node[anchor=west] {$t_{2g}$};

\foreach \b in {4,5,6} {
\draw[black,thick] (\b,5) -- (\b+0.5,5);
\draw[black,thick] (\b,1.4) -- (\b+0.5,1.4);
};

\node at (4.25,4.5) {$d_{z^2}$};
\node at (5.25,4.5) {$d_{x^2-y^2}$};

\node at (5,3.2) {S=2};

\node at (4.25,0.9) {$d_{xy}$};
\node at (5.25,0.9) {$d_{xz}$};
\node at (6.25,0.9) {$d_{yz}$};

\draw[black,dashed,<->] (6.5,1.4) -- (6.5,5);

\node at (7,3.2) {$\Delta$};

\draw[ultra thick,blue!50,dashed] (7.5,0.9) -- (7.5,5.5);

\draw[black,dotted] (6.5,1.4) -- (8.5,1);
\draw[black,dotted] (6.5,5) -- (8.5,5.4);

\draw [-{Triangle[left]},ultra thick,red]  (4.25,4.8) -- (4.25,5.5);
\draw [-{Triangle[left]},ultra thick,red]  (5.25,4.8) -- (5.25,5.5);

\draw [-{Triangle[left]},ultra thick,red]  (4.2,1.2) -- (4.2,1.9);
\draw [{Triangle[left]}-,ultra thick,red]  (4.3,1.2) -- (4.3,1.9);
\draw [-{Triangle[left]},ultra thick,red]  (5.25,1.2) -- (5.25,1.9);
\draw [-{Triangle[left]},ultra thick,red]  (6.25,1.2) -- (6.25,1.9);

\node at (5,6) {$\Delta < P$};

\foreach \b in {8.5,9.5,10.5} {
\draw[black,thick] (\b,5.4) -- (\b+0.5,5.4);
\draw[black,thick] (\b,1) -- (\b+0.5,1);
};

\node at (9.5,6) {$\Delta > P$};

\node at (9.5,3.2) {S=0};

\node at (10.5,3.2) {$\Delta$};

\draw[black,dashed,<->] (10.25,1) -- (10.25,5.4);

\draw [-{Triangle[left]},ultra thick,red]  (8.7,0.8) -- (8.7,1.5);
\draw [-{Triangle[left]},ultra thick,red]  (9.7,0.8) -- (9.7,1.5);
\draw [-{Triangle[left]},ultra thick,red]  (10.7,0.8) -- (10.7,1.5);
\draw [{Triangle[left]}-,ultra thick,red]  (8.8,0.8) -- (8.8,1.5);
\draw [{Triangle[left]}-,ultra thick,red]  (9.8,0.8) -- (9.8,1.5);
\draw [{Triangle[left]}-,ultra thick,red]  (10.8,0.8) -- (10.8,1.5);

\node[red,ultra thick] at (5,0.25) {\textbf{high-spin}};

\node[blue,ultra thick] at (10,0.25) {\textbf{low-spin}};
\end{tikzpicture}

\end{document}
• Nice solution! I believe that it is sufficient to load only pgfplots and not tikz twice and additionally pgdfplots :). For pgplots is good to define compatibility with \pgfplotsset{compat=.... Mar 10 '17 at 20:04