I need some help drawing a NH3 molecular orbital. I've made a drawing off how it should look like (but it looks ugly, the proportions are wrong and and and). It would be nice if you could help me drawing such a diagram. All the text used in on the sketch should be used, but please all in black, colors was only used to show how it should look like. Hopefully you can help me. What should I use? Tikz or Modiagram?

The energies in [eV] are:

  • 2s: -26.2

  • 2p: -13.8

  • 1s: -13.6

Here my sketch: NH3-sketch.

And this is what I tried Modiagram:


\atom{left}[N] {2s=2;}
\atom{left} {2p=5;,,}
\atom{right}[\ce{H_3}] {1s=0}


It didn't worked the way I wanted it to. One of the greater problems I have is, that I can't find MO in LaTeX which are so complex as my diagram. So it would be really nice, if you could help me :-)

1 Answer 1


I fear, you have to set those manually:

% arara: pdflatex


        \AO(1cm){s}[label={2s}]{0.5;} % AO1
        \AO(1cm){s}[label={2p}]{2;} % AO2
        \AO(1cm){s}{2.1;} % AO3
        \AO(1cm){s}{2.2;} % AO4
        \node at (1cm, -1){N};
        \AO(3cm){s}[label={$2\mathrm{a}_1$}]{0;pair} % AO5
        \AO(3cm){s}[label={1e}]{0.9;pair} % AO6
        \AO(3cm){s}{1.1;pair} % AO7
        \AO(3cm){s}[label={$3\mathrm{a}_1$}]{2;pair} % AO8
        \AO(3cm){s}[label={$4\mathrm{a}_1$}]{3;} % AO9
        \AO(3cm){s}[label={2e}]{3.9;} % AO10
        \AO(3cm){s}{4.1;} % AO11
        \node at (3cm, -1){\ce{NH_3}};
        \connect{AO1 & AO6, AO1 & AO7, AO1 & AO8}
        \connect{AO4 & AO8, AO4 & AO9, AO4 & AO10, AO4 & AO11}
        \AO(5cm){s}[label={1s}]{2.5;} % AO12
        \node at (5cm, -1){H};
        \connect{AO5 & AO12, AO6 & AO12, AO7 & AO12, AO8 & AO12, AO9 & AO12, AO10 & AO12, AO11 & AO12, }

enter image description here

modiagram does not support those double and triple lines. Please read the documentation for all the features and well explained examples.

  • @BasiliusSapientia You are welcome!
    – LaRiFaRi
    Mar 2, 2015 at 22:07
  • 2
    You can use \AO's label option to add description: \AO(1cm){s}[label={2s}]{0.5}
    – cgnieder
    Mar 3, 2015 at 9:54
  • 1
    Fantastic modiagramtutorial :)
    – Mats
    Sep 6, 2016 at 9:51

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