Math & Science ⇒ chemfig: how to rappresent rocking and scissoring vibration

[Molibdeno]

Infrared spectroscopy is based on the principle that radiation with a wavelength between 25000 nm and 40000 nm is absorbed by the molecule altering its vibrational movements. There are various ways to alter the molecule vibrations : for example, for water we can have a bond lenght change

Code: Select all

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{textcomp}
\usepackage[italian]{babel}
\usepackage[
  a4paper,
  margin=15mm,
  bindingoffset=2mm,
  heightrounded,
]{geometry}

\usepackage{amsmath}
\usepackage{chemfig}
\usepackage[version=3]{mhchem}
% motivated by section 15.6 of the pgfmanual, @percusses comment https://tex.stackexchange.com/questions/423941/making-the-determination-of-extrema-more-elegant-in-tikz-not-pgfplots#comment1060557_423941
% as well as Henri Menkes's answer https://tex.stackexchange.com/a/423952/121799
\tikzset{mark path bounding box/.style = {
    path picture={
      \coordinate (#1-bl) at (path picture bounding box.south west);
      \coordinate (#1-tr) at (path picture bounding box.north east);
      \coordinate (#1-br) at (path picture bounding box.south east);
      \coordinate (#1-tl) at (path picture bounding box.north west);
    }
  }
}

\begin{document}

\schemestart
\chemname{\chemfig{@{H1}H-[:30]@{O1}O-[:-30]@{H2}H}}{Stretching simmetrico}
\schemestop
\chemmove{\path[mark path bounding box=HO](H1)--(O1);
\draw[blue,-latex]([yshift=2mm,xshift=-1mm]HO-bl)--([yshift=2mm,xshift=-1mm]HO-tr);
\path[mark path bounding box=OH](H2)--(O1);
\draw[blue,-latex]([yshift=2mm,xshift=1mm]OH-br)--([yshift=2mm,xshift=1mm]OH-tl);
}
\hspace{64pt}
\schemestart
\chemname{\chemfig{@{H1}H-[:30]@{O1}O-[:-30]@{H2}H}}{Stretching asimmetrico}
\schemestop
\chemmove{\path[mark path bounding box=HO](H1)--(O1);
\draw[blue,-latex]([yshift=2mm,xshift=-1mm]HO-bl)--([yshift=2mm,xshift=-1mm]HO-tr);
\path[mark path bounding box=HO](O1)--(H2);
\draw[blue,-latex]([yshift=2mm,xshift=1mm]HO-tl)--([yshift=2mm,xshift=1mm]HO-br);
}
\end{document}

Instead rocking and scissoring cause a variation of the bond angle



I add the blue arrow with Inkscape. Is it possible do the same thing with LaTeX? If so, could you tell me how?

Thank you in advance