\Section{band}
    \desc{Band theory}{}{}
    \desc[german]{Bändermodell}{}{}

    \Subsection{hybrid_orbitals}
        \desc{Hybrid orbitals}{Hybrid orbitals are linear combinations of other atomic orbitals.}{}
        \desc[german]{Hybridorbitale}{Hybridorbitale werden durch Linearkombinationen von anderen atomorbitalen gebildet.}{}  

    % chemmacros package
    \begin{formula}{sp}
        \desc{sp Orbital}{\GT{eg} \ce{C2H2}}{}
        \desc[german]{sp Orbital}{}{}
        \ttxt{\eng{Linear with bond angle \SI{180}{\degree}}\ger{Linear mit Bindungswinkel \SI{180}{\degree}}}
        \eq{
            1\text{s} + 1\text{p} = \text{sp}
            \orbital{sp}
        }
    \end{formula}

    \begin{formula}{sp2}
        \desc{sp2 Orbital}{\GT{eg} \ce{C2H4}}{}
        \desc[german]{sp2 Orbital}{}{}
        \ttxt{\eng{Trigonal planar with bond angle \SI{120}{\degree}}\ger{Trigonal planar mit Bindungswinkel \SI{120}{\degree}}}
        \eq{
            1\text{s} + 2\text{p} = \text{sp2} 
            \orbital{sp2}  
            % \\ \ket{p} = \cos\theta \ket{p_x} + \sin\theta \ket{p_y}
        }
    \end{formula}

    \begin{formula}{sp3}
        \desc{sp3 Orbital}{\GT{eg} \ce{CH4}}{}
        \desc[german]{sp3 Orbital}{}{}
        \ttxt{\eng{Tetrahedral with bond angle \SI{109.5}{\degree}}\ger{Tetraedisch mit Bindungswinkel \SI{109.5}{\degree}}}
        \eq{
            1\text{s} + 3\text{p} = \text{sp3}
            \orbital{sp3}
        }
    \end{formula}

    \begin{formula}{wave_function}
        \desc{Wave function}{of a hybrid orbital}{$N$ number of involved $p$ orbitals}
        \desc[german]{Wellenfunktion}{eines Hybridorbitals}{$N$ Anzahl der beteiligten $p$ Orbitale}
        \eq{\ket{h_{1\dots N+1}} = \frac{1}{\sqrt{N+1}} \left(\ket{s} + \sqrt{N} \ket{p}\right)}
    \end{formula}



\Section{diffusion}
    \desc{Diffusion}{}{}
    \desc[german]{Diffusion}{}{}    
    \begin{formula}{diffusion_coefficient}
        \desc{Diffusion coefficient}{}{}
        \desc[german]{Diffusionskoeffizient}{}{}
        \quantity{D}{\m^2\per\s}{s}
    \end{formula}

    \begin{formula}{particle_current_density}
        \desc{Particle current density}{Number of particles through an area}{}
        \desc[german]{Teilchenstromdichte}{Anzahl der Teilchen durch eine Fläche}{}
        \quantity{J}{1\per\s^2}{s}
    \end{formula}

    \begin{formula}{einstein_relation}
        \desc{Einstein relation}{Classical}{\QtyRef{diffusion_coefficient}, \mu \qtyRef{mobility}, \QtyRef{temperature}, $q$ \qtyRef{charge}}
        \desc[german]{Einsteinrelation}{Klassisch}{}
        \eq{D = \frac{\mu \kB T}{q}}
    \end{formula}   

    \begin{formula}{concentration}
        \desc{Concentration}{A quantity per volume}{}
        \desc[german]{Konzentration}{Eine Größe pro Volumen}{}
        \quantity{c}{x\per\m^3}{s}
    \end{formula}

    \begin{formula}{fick_law_1}
        \desc{Fick's first law}{Particle movement is proportional to concentration gradient}{\QtyRef{particle_current_density}, \QtyRef{diffusion_coefficient}, \QtyRef{concentration}}
        \desc[german]{Erstes Ficksches Gesetz}{Teilchenbewegung ist proportional zum Konzentrationsgradienten}{}
        \eq{J = -D\frac{c}{x}}
    \end{formula}

    \begin{formula}{fick_law_2}
        \desc{Fick's second law}{}{\QtyRef{particle_current_density}, \QtyRef{diffusion_coefficient}, \QtyRef{concentration}}
        \desc[german]{Zweites Ficksches Gesetz}{}{}
        \eq{\pdv{c}{t} = D \pdv[2]{c}{x}}
    \end{formula}

\Section{misc}
    % \desc{\GT{misc}}{}{}
    % \desc[german]{\GT{misc}}{}{}


    \begin{formula}{vdw_material}
        \desc{Van-der-Waals material}{2D materials}{}
        \desc[german]{Van-der-Waals Material}{2D Materialien}{}
        \ttxt{\eng{
            Materials consiting of multiple 2D-layers held together by Van-der-Waals forces.
        }\ger{
            Aus mehreren 2D-Schichten bestehende Materialien, die durch Van-der-Waals Kräfte zusammengehalten werden.
        }}
    \end{formula}


    \begin{formula}{work_function}
        \desc{Work function}{Lowest energy required to remove an electron into the vacuum}{}
        \desc[german]{Austrittsarbeit}{eng. "Work function"; minimale Energie um ein Elektron aus dem Festkörper zu lösen}{}
        \quantity{W}{\eV}{s}
        \eq{W = \Evac - \EFermi}
    \end{formula}

    \begin{formula}{electron_affinity}
        \desc{Electron affinity}{Energy required to remove one electron from an anion with one negative charge.\\Energy difference between vacuum level and conduction band}{}
        \desc[german]{Elektronenaffinität}{Energie, die benötigt wird um ein Elektron aus einem einfach-negativ geladenen Anion zu entfernen. Entspricht der Energiedifferenz zwischen Vakuum-Niveau und dem Leitungsband}{}
        \quantity{\chi}{\eV}{s}
        \eq{\chi = \left(\Evac - \Econd\right)}
    \end{formula}


    \begin{formula}{laser}
        \desc{Laser}{Light amplification by stimulated emission of radiation}{}
        \desc[german]{Laser}{}{}
        \ttxt{
            \eng{\textit{Gain medium} is energized \textit{pumping energy} (electric current or light), light of certain wavelength is amplified in the gain medium}
        }
    \end{formula}

    \begin{formula}{vacuum}
        \desc{Vacuum ranges}{}{}
        \desc[german]{Vakuumklassen}{}{}
        \ttxt{\eng{
            \begin{itemize}
                \item \textbf{Rough vacuum}: \SI{1}{\atm} - \SI{10e-2}{\milli\bar} \\ viscous flow
                \item \textbf{Process vacuum}: \SI{10e-2}{\milli\bar} - \SI{10e-4}{\milli\bar} \\ \abbrRef{mfp} $\le$ chamber size
                \item \textbf{High vacuum}: \SI{10e-5}{\milli\bar} - \SI{10e-9}{\milli\bar} \\ \abbrRef{mfp} $>$ chamber size, mostly residual \ce{H20} vapor
                \item \textbf{Ultra-high vacuum}: $<$ \SI{10e-9}{\milli\bar} \\ \abbrRef{mfp} $\gg$ chamber size, mostly residual \ce{H2}
            \end{itemize}
        }\ger{
            \TODO{translate}
        }}
    \end{formula}
