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

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Molibdeno
Posts: 10
Joined: Fri Apr 07, 2017 12:15 pm

### chemfig: how to rappresent rocking and scissoring vibration

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

\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 <!-- m --><a class="postlink" href="https://tex.stackexchange.com/questions/423941/making-the-determination-of-extrema-more-elegant-in-tikz-not-pgfplots#comment1060557_423941">https://tex.stackexchange.com/questions ... 557_423941</a><!-- m -->% as well as Henri Menkes's answer <!-- m --><a class="postlink" href="https://tex.stackexchange.com/a/423952/121799">https://tex.stackexchange.com/a/423952/121799</a><!-- m -->\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?