Opening ORCA Molecular Orbital Generations in Avogadro 1.97.0

I cannot seem to figure out, despite reading a large amount of documentation online, how to open MO output from Orca. Im new to using orca, and this is my first time trying MO but on my windows machine i was able to get it to work in avogadro1. I can open the output file, but cant seem to find any way to visualize MO’s.

Below is a list of specs:

Open Babel 3.1.1
Avogadro 1.97.0
Kubuntu 6.2.0-27-generic #28-Ubuntu SMP PREEMPT_DYNAMIC Wed Jul 12 22:39:51 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
Orca 5.0.4

Here are the input and output files.

Input: Hastebin
Output: Hastebin

Note, in an earlier answer here (May 2021), Geoff recommended

I generally use orca_2mkl basename -molden to generate a Molden file.
(I’d like to see support for mkl files too, so help welcome.)

To add to Thomas’s comment, Orca had an “enhanced” version with a direct Orca output reader. I will work to port this to 1.98 / 1.99, but I don’t know how long that will take without help.


  • Generate a molden file
  • Install cclib and the avogadro-cclib extension and read your Orca through cclib

The latter works well for a wide range of output, and cclib continues to update.

I am able to get functional inputs in Avogadro 1.2 using molden files. I can import files with cclib and molden in avogadro 2, however unlike 1.2 I am unable to visualize MO’s. Here is the molden file I am using:

I had read that thread already and tried molden and the results is almost always the same. I end up with the initial CH4, but no HUMO LUMO analysis.

@Astrochemist Potential bypass: Though it doesn’t appear on Jmol’s list of coordinate files accessible, load the molden file there. If you then right-click somewhere on the canvas of the program, there is a pulldown menu, choose Surfaces → Molecular Orbitals to display one of the 34 orbitals identified:


output.molden.gz (10.5 KB)

This is a functional solution. I can open and view results in Jmol via your recommendations. I am looking forward to this ability in Avogadro, and if there is anything I can do to assist development, I would like to.

Thank you for the work-around for now.

I have good news. I took a bit of time and ported the Orca code to Avo2. It definitely needs cleanup before it’s ready for release, but I can definitely read your file:

The pull request is here: