Drawing energy diagram involving transitions [closed]

Question

I want to draw energy diagram involving transitions in latex. I want to draw the following diagram.

I know it is possible to draw it element by element using tikz. But still I am interested to know is there any method to draw it with minimal effort.

Answer 1

Well, unfortunately endiagram won't work in this case, so I revered to using TikZ. The code below is based on using LuaLaTeX / XeLaTeX as compiler. You can change the fonts loaded according to your compiler, say \usepackage{gfsartemisia} when using PDFLaTeX.

The code that will give you your diagram looks like this:

\documentclass[a4paper,11pt]{article}

\usepackage{polyglossia}
\setdefaultlanguage[babelshorthands=true]{dutch}
\setotherlanguage[variant=british]{english}

\usepackage[sans-style=upright]{unicode-math} % automatically loads fontspec package
\defaultfontfeatures{Scale = MatchLowercase}
\setmainfont{GFSArtemisia}[
    Scale=1.00,
    Extension = .otf,
    UprightFont = *,
    ItalicFont = *It,
    BoldFont = *Bold,
    BoldItalicFont = *BoldIt]

\setsansfont{Nunito}[
    Extension = .otf,
    UprightFont = *-Regular,
    ItalicFont = *-Italic,
    BoldFont = *-Bold,
    BoldItalicFont = *-BoldItalic]

\setmathfont{XITSMath-Regular.otf}

\usepackage[body={17.0cm,26cm},top=2.0cm,left=2.0cm]{geometry}
\usepackage{endiagram}

\setlength{\parindent}{0pt}
\renewcommand{\baselinestretch}{1.1}

\usepackage{tikz}
\usetikzlibrary{arrows,arrows.meta,backgrounds,calc,decorations,decorations.markings,decorations.pathmorphing,fit,positioning,shapes.arrows,shapes.callouts,shapes.geometric,shapes.misc}

\begin{document}
    
\begin{endiagram}[axes=y]
    \ENcurve[step=0.9]{0,4,3,1,0}
    \ShowNiveaus
\end{endiagram}

\begin{tikzpicture}[decoration={snake}]
    %== drawing the levels
    \draw[very thick,black,-{Stealth[length=3mm]}] (0.5,0) --(0.5,6);
    \draw[very thick,blue] (0,0) -- (4,0) node(t1) [align=left,xshift=7mm] {1 ($\tau_1$)};
    \draw[very thick,blue] (0,6) -- (4,6) node(t2) [align=left,xshift=7mm] {2 ($\tau_2$)};
    \draw[very thick,blue] (2,4) -- (4,4) node(t3) [align=left,xshift=7mm] {3 ($\tau_3$)};
    \draw[very thick,blue] (2,2) -- (4,2) node(t4) [align=left,xshift=7mm] {4 ($\tau_4$)};
    
    %== drawing the decays
    \draw[thick,decorate,black,-{Stealth[length=3mm]}] (2.4,6) -- node(d1) [right,align=left,xshift=2mm,font=\footnotesize] {non-radiative \\ fast decay} (2.4,4);
    \draw[thick,black,-{Stealth[length=3mm]}] (2.4,4) -- node(d2) {} (2.4,2);
    \draw[thick,decorate,red,-{Stealth[length=3mm]}] (2.5,3) -- node(rd) [above,align=left,yshift=1mm,font=\footnotesize] {$h\nu$} (3.8,3);
    \draw[thick,decorate,black,-{Stealth[length=3mm]}] (2.4,2) -- node(d3) [right,align=left,xshift=2mm,font=\footnotesize] {non-radiative \\ very fast decay} (2.4,0);
    
    %== annotating levels
    \node[right=of t2] {$\tau_2 \ll \tau_3$};
    \node[right=of t3] {$\tau_3 \gg \tau_4$};
    \node[draw,rectangle callout,callout absolute pointer={(t3.south east)},font=\footnotesize] at (7,3.4) {meta stable};
\end{tikzpicture}       
    
    
\end{document}

The output including the use of endiagram gives: