# Incorrect MO number in creating surface from MOPAC results **URL:** \ **Category:** Support\ **Created:** [November 14, 2025, 8:27am UTC](https://discuss.avogadro.cc/t/incorrect-mo-number-in-creating-surface-from-mopac-results/7228 "2025-11-14T08:27:05Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![tsubomura](https://discuss.avogadro.cc/letter_avatar_proxy/v4/letter/t/958977/32.png) [@tsubomura](https://discuss.avogadro.cc/u/tsubomura)\ **Post date:** [November 14, 2025, 8:27am UTC](https://discuss.avogadro.cc/t/incorrect-mo-number-in-creating-surface-from-mopac-results/7228/1 "2025-11-14T08:27:05Z")
I would like to use Avogadro to depict Molecular orbitals using the aux files calculated by OpenMOPAC2016 software. The MO number seems to be invalid if I calculate MO surface in the “Analyze” → “create surface” menu. For example, water molecule has six valence MOs, 1 - 6. The MO 2,3,4,5,6 showed in the avogadro seems to be actually MO 1,2,3,4,5. Is this bug? ## Environment Information Avogadro version: 1.102.1 Operating system and version: windows 11 ## ---
**Author:** ![ghutchis](https://discuss.avogadro.cc/user_avatar/discuss.avogadro.cc/ghutchis/32/456_2.png) [@ghutchis](https://discuss.avogadro.cc/u/ghutchis)\ **Post date:** [November 14, 2025, 12:46pm UTC](https://discuss.avogadro.cc/t/incorrect-mo-number-in-creating-surface-from-mopac-results/7228/2 "2025-11-14T12:46:36Z")
Can you upload an example file? I don’t have MOPAC 2016 anymore. ---
**Author:** ![tsubomura](https://discuss.avogadro.cc/letter_avatar_proxy/v4/letter/t/958977/32.png) [@tsubomura](https://discuss.avogadro.cc/u/tsubomura)\ **Post date:** [November 14, 2025, 1:59pm UTC](https://discuss.avogadro.cc/t/incorrect-mo-number-in-creating-surface-from-mopac-results/7228/3 "2025-11-14T13:59:09Z")
Hi ghutchis, Thank you for your comments. Here I upload an MOPAC output file, H2O.txt. Please rename this to H2O.aux, and read it with avogadro. I can see the MO surface, but the MO number is incorrect. [h2oaux.txt](https://discuss.avogadro.cc/uploads/short-url/mdG6n1u2zewFuQPgmSjEBtzB1Re.txt) (3.1 KB) ---
**Author:** ![Thomas](https://discuss.avogadro.cc/user_avatar/discuss.avogadro.cc/thomas/32/3403_2.png) [@Thomas](https://discuss.avogadro.cc/u/Thomas)\ **Post date:** [November 14, 2025, 9:22pm UTC](https://discuss.avogadro.cc/t/incorrect-mo-number-in-creating-surface-from-mopac-results/7228/4 "2025-11-14T21:22:02Z")
> [@ghutchis](#): > > I don’t have MOPAC 2016 anymore MOPAC2016 eventually became [OpenMOPAC](http://openmopac.net/) with own public [GitHub repository](https://github.com/openmopac/mopac) running under the permissive Apache 2.0 license scheme. Thus, beside [official releases](https://github.com/openmopac/mopac/releases), the program equally is packaged by DebiChem ([tracker page](https://tracker.debian.org/pkg/mopac)) and other platforms. Jonathan E. Moussa (the current lead developer) welcomes every interested contributor to the project. ---
**Author:** ![ghutchis](https://discuss.avogadro.cc/user_avatar/discuss.avogadro.cc/ghutchis/32/456_2.png) [@ghutchis](https://discuss.avogadro.cc/u/ghutchis)\ **Post date:** [November 14, 2025, 11:16pm UTC](https://discuss.avogadro.cc/t/incorrect-mo-number-in-creating-surface-from-mopac-results/7228/5 "2025-11-14T23:16:40Z")
> [@Thomas](#): > > MOPAC2016 eventually became [OpenMOPAC](http://openmopac.net/) with own public [GitHub repository](https://github.com/openmopac/mopac) running under the permissive Apache 2.0 license scheme Yep. I know - I helped Jimmy Stewart out a few times. At one point, he was getting NIH funding for MOPAC but needed a support letter saying that Avogadro would help providing a UI to visualize MOPAC results. I’m happy to see that it’s getting updates and maintenance now. What I meant more was “I haven’t used MOPAC in a while, but I’ll definitely check it out.” Certainly we should check to make sure that the MOPAC support still works with the most recent releases of OpenMOPAC. And I’ll take a look at the MO numbering later tonight. ---
**Author:** ![tsubomura](https://discuss.avogadro.cc/letter_avatar_proxy/v4/letter/t/958977/32.png) [@tsubomura](https://discuss.avogadro.cc/u/tsubomura)\ **Post date:** [November 15, 2025, 2:53am UTC](https://discuss.avogadro.cc/t/incorrect-mo-number-in-creating-surface-from-mopac-results/7228/6 "2025-11-15T02:53:59Z")
I use the MOPAC software obtained from the site, [Downloads](http://openmopac.net/Download_MOPAC_Executable_Step2.html) . I hope the situation will be clarified. ---
**Author:** ![ghutchis](https://discuss.avogadro.cc/user_avatar/discuss.avogadro.cc/ghutchis/32/456_2.png) [@ghutchis](https://discuss.avogadro.cc/u/ghutchis)\ **Post date:** [November 16, 2025, 5:12am UTC](https://discuss.avogadro.cc/t/incorrect-mo-number-in-creating-surface-from-mopac-results/7228/7 "2025-11-16T05:12:25Z")
Yes - I can confirm that MO 1 seems to be empty, and the other orbitals are offset by one. I’m trying to figure out _why_ .. or more particularly what part of the code is doing that. ---
**Author:** ![ghutchis](https://discuss.avogadro.cc/user_avatar/discuss.avogadro.cc/ghutchis/32/456_2.png) [@ghutchis](https://discuss.avogadro.cc/u/ghutchis)\ **Post date:** [November 16, 2025, 5:38am UTC](https://discuss.avogadro.cc/t/incorrect-mo-number-in-creating-surface-from-mopac-results/7228/8 "2025-11-16T05:38:19Z")
Okay, this should fix it. I’ll merge in the morning, and it should be in the continuous releases: [Release continuous · OpenChemistry/avogadrolibs · GitHub](https://github.com/openchemistry/avogadrolibs/releases/continuous) MO6 for water (previously invisible): ![MO6 for water from MOPAC aux file](https://discuss.avogadro.cc/uploads/default/original/2X/f/f364c7f243a1561311a79cb497f57ff34ea87740.png) > > > Thanks to tsubomura for reporting the bug > > Developer Certificate of Origin > Ve…rsion 1.1 > > Copyright (C) 2004, 2006 The Linux Foundation and its contributors. > 1 Letterman Drive > Suite D4700 > San Francisco, CA, 94129 > > Everyone is permitted to copy and distribute verbatim copies of this > license document, but changing it is not allowed. > > > Developer's Certificate of Origin 1.1 > > By making a contribution to this project, I certify that: > > (a) The contribution was created in whole or in part by me and I > have the right to submit it under the open source license > indicated in the file; or > > (b) The contribution is based upon previous work that, to the best > of my knowledge, is covered under an appropriate open source > license and I have the right under that license to submit that > work with modifications, whether created in whole or in part > by me, under the same open source license (unless I am > permitted to submit under a different license), as indicated > in the file; or > > (c) The contribution was provided directly to me by some other > person who certified (a), (b) or (c) and I have not modified > it. > > (d) I understand and agree that this project and the contribution > are public and that a record of the contribution (including all > personal information I submit with it, including my sign-off) is > maintained indefinitely and may be redistributed consistent with > this project or the open source license(s) involved. ---
**Author:** ![tsubomura](https://discuss.avogadro.cc/letter_avatar_proxy/v4/letter/t/958977/32.png) [@tsubomura](https://discuss.avogadro.cc/u/tsubomura)\ **Post date:** [November 17, 2025, 9:05am UTC](https://discuss.avogadro.cc/t/incorrect-mo-number-in-creating-surface-from-mopac-results/7228/9 "2025-11-17T09:05:27Z")
Thank you very much for your very fast work. I confirmed fixation of the software, continuous release, using the data of some simple molecules. I had been using Avogdro1 for studying the spectroscopic properties of some metal complexes, but (recently I retired from the research) I would like to use Avogadro2 for educational purpose. ---
**Author:** ![ghutchis](https://discuss.avogadro.cc/user_avatar/discuss.avogadro.cc/ghutchis/32/456_2.png) [@ghutchis](https://discuss.avogadro.cc/u/ghutchis)\ **Post date:** [November 17, 2025, 3:00pm UTC](https://discuss.avogadro.cc/t/incorrect-mo-number-in-creating-surface-from-mopac-results/7228/10 "2025-11-17T15:00:10Z")
> [@tsubomura](#): > > I would like to use Avogadro2 for educational purpose. You may also want to look at XTB / GFN2 for educational purposes. In general, I’ve found it to be more accurate, although it doesn’t directly give heats of formation. ---
**Author:** ![tsubomura](https://discuss.avogadro.cc/letter_avatar_proxy/v4/letter/t/958977/32.png) [@tsubomura](https://discuss.avogadro.cc/u/tsubomura)\ **Post date:** [November 18, 2025, 12:53am UTC](https://discuss.avogadro.cc/t/incorrect-mo-number-in-creating-surface-from-mopac-results/7228/11 "2025-11-18T00:53:15Z")
Thank you for your information. I have not known the method, XTB / GFN2. I will check it out 😀 ---
**Author:** ![system](https://discuss.avogadro.cc/uploads/default/original/1X/93fe5a56d10b304e678127e54139c28cde211662.png) [@system](https://discuss.avogadro.cc/u/system)\ **Post date:** [November 21, 2025, 12:53am UTC](https://discuss.avogadro.cc/t/incorrect-mo-number-in-creating-surface-from-mopac-results/7228/12 "2025-11-21T00:53:45Z")
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