How to draw rotational level diagrams in LaTeX?

Question

The gorgeous picture below represents the relation between the quantum number J and a interesting parameter - the Ray asymmetry parameter -, which relates the three dimensional inertia moments of a given molecule. In other words, for the same type of rotational transition, how the energy changes with the shape of the molecule, as it goes from a prolate (rugby-ball shape) to a spheroid and finally into an oblate (a frisbee-like shape).

I am trying to depict it in LaTeX but I can't get the labels properly. any idea would be greatly appreciated!

Below you'll find my MWE (inspired from the link posted by putianyi888)

\documentclass[tikz]{standalone}
\usetikzlibrary{shapes.callouts}
\tikzset{
    level/.style = {
        ultra thick,
        blue,
    },
    connect/.style = {
        dashed,
        red
    },
    notice/.style = {
        draw,
        rectangle callout,
        callout relative pointer={#1}
    },
    label/.style = {
        text width=2cm
    }
}
\begin{document}
    \begin{tikzpicture}



\draw[level](2,0) -- node[above] {left} (3,0); \draw[connect](3,0) -- (7,0); \draw[level](7,0) -- (8,0);

\draw[level](2,2) -- (3,2); \draw[connect](3,2) -- node[below](7,3); \draw[level](7,3) -- (8,3); \draw[connect](3,2) -- (7,1); \draw[level](7,1) -- (8,1);


\end{tikzpicture}
\end{document}

score 4 · Answer 1 · answered Nov 27 '19 at 11:40

4

Have you checked this thread? Energy level diagrams with TeX

I don't have enough reputations to comment, so I put it as my answer.

answered Nov 27 '19 at 11:40

putianyi888

137

Yes, I did - I even tried to adapt it, but I was unable to attain the necessary results... Not so much a question of finding stuff, but more a question of skill, unfortunately! – Strelok Nov 27 '19 at 11:48

Jasper Habicht · Accepted Answer · 2019-11-28T22:30:23.793

You can place nodes inside the \draw macros and shift them to the left or right. This way, you can properly align the nodes. Like this, for example:

\documentclass[tikz]{standalone}
\tikzset{
    level/.style = {
        ultra thick,
        blue,
    },
    connect/.style = {
        dashed,
        red
    },
    label/.style = {
        align=center,
        text width=3em,
        text depth=0pt, 
    },
    labela/.style = {
        label,
        xshift=-2.5em
    },
    labelb/.style = {
        labela,
        xshift=1.5em
    },
    labelc/.style = {
        label,
        xshift=1.25em
    },
    labeld/.style = {
        label,
        xshift=1em
    },
    labele/.style = {
        labeld,
        xshift=1.5em
    }
}

\begin{document}
\begin{tikzpicture}

\draw[level](2,0) node[labela] {$3$} node[labelb] {$2$} -- ++(1,0); 
\draw[level](2,2) node[labela] {$3$} node[labelb] {$3$} -- ++(1,0); 

\draw[level](7,0) -- ++(1,0) node[labelc] {$3_{21}$} ;
\draw[level](7,3) -- ++(1,0) node[labelc] {$3_{30}$} ; 
\draw[level](7,1) -- ++(1,0) node[labelc] {$3_{31}$} ;

\draw[level](12,4) -- ++(1,0) node[labeld] {$3$} node[labele] {$0$} ;
\draw[level](12,3) -- ++(1,0) node[labeld] {$3$} node[labele] {$1$} ;

\draw[connect](3,0) -- (7,0); 
\draw[connect](3,2) -- (7,3); 
\draw[connect](3,2) -- (7,1); 
\draw[connect](8,3) -- (12,4); 
\draw[connect](8,1) -- (12,3); 
\draw[connect](8,0) -- (12,3); 

\node[labela] at (2,-1) {$J$};
\node[labelb] at (2,-1) {$K_{a}$};
\node[labelc] at (8,-1) {$J_{K_{a}K_{c}}$};
\node[labeld] at (13,-1) {$J$};
\node[labele] at (13,-1) {$K_{c}$};

\node at (2.5,-1.5) {$(a)$};
\node at (7.5,-1.5) {$(b)$};
\node at (12.5,-1.5) {$(c)$};

\end{tikzpicture}
\end{document}

Result:

Awesome! Just what I needed! Kudos!!! – Strelok Nov 29 '19 at 10:43 — Strelok, Nov 29 '19 at 10:43

How to draw rotational level diagrams in LaTeX?

2 Answers2