Chemical reaction

Question

Good morning, everyone,

I am a Bachelor of Science in Physics student, and I would like to be able to reproduce the routing of this example here on Latex, not necessarily draw the molecules, I learn on the job (thanks to the Net).

I tried with tikz, and chemfig, but I have something very academic, if not primary. Indeed, I would like to be able to draw the big arrow on the left and the three arrows down, vary their size.

This would allow me to build my own reactions.

Thank you very much.

I'm sorry, I forgot to insert the links

https://pubs.acs.org/na101/home/literatum/publisher/achs/journals/content/jpcafh/2008/jpcafh.2008.112.issue-5/jp709896w/production/images/medium/jp709896wh00001.gif

I'm interested in the middle arrow here, and here's the document I was talking about.

https://pubs.acs.org/na101/home/literatum/publisher/achs/journals/content/jpcafh/2008/jpcafh.2008.112.issue-5/jp709896w/production/images/medium/jp709896wh00002.gif

My simple routine :

\documentclass{scrartcl}
\usepackage{tikz-cd}
\begin{document}
\begin{tikzcd}
& 0  \arrow{r}{a} \arrow{r}[swap]{b}                                  
& 1  \arrow{r}{a} \arrow{r}[swap]{b}                                  
& 2  \arrow{d}{a} \arrow{d}[swap]{b}                                                 
& \\
& 5  \arrow{d}{a} \arrow{d}[swap]{b}               
& 4  \arrow{l}{a} \arrow{l}[swap]{b}  
& 3  \arrow{l}{a} \arrow{l}[swap]{b}
&\\
& 6  \arrow{r}{a} \arrow{r}[swap]{b}
& 7  \arrow{r}{a} \arrow{r}[swap]{b}
& 8  \arrow{d}{a} \arrow{d}[swap]{b}
&\\
& 11                                                   
& 10 \arrow{l}{a} \arrow{l}[swap]{b} 
& 9  \arrow{l}{a} \arrow{l}[swap]{b}
\end{tikzcd}
\end{document}

Answer 1

Guessing that the question is about merged arrows, the following two small examples might serve as a starting point:

\documentclass{article}
\usepackage{chemfig}

\begin{document}

\schemestart
  A
  \arrow(a--b){->[Text2]}[,1.0]
  B
  \arrow(@a--c){->[][*{0} Text1]}[-90]
  C
   \merge>(c)(b)--()D
\schemestop

\bigskip

\schemestart
  A
  \arrow(a--b){->[Text2]}[,1.0]
  B
  \arrow(@a--c){->[][*{0} Text1]}[-90]
  C
  \arrow(@c--d){->[][Text3]}[,2.5]
  D
\schemestop
\makeatletter
\chemmove{
  \draw[-CF ,shorten <=\CF@arrow@offset,shorten >=\CF@arrow@offset]
    (b) |- node[pos=.7,right] {} (d) ;
}
\makeatother

\end{document}