# Error in Hbond

**URL:** <https://gromacs.bioexcel.eu/t/error-in-hbond/9891>\
**Category:** User discussions\
**Tags:** analysis-tools\
**Created:** [August 15, 2024, 6:22pm UTC](https://gromacs.bioexcel.eu/t/error-in-hbond/9891 "2024-08-15T18:22:00Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![maham](https://avatars.discourse-cdn.com/v4/letter/m/c77e96/32.png) [@maham](https://gromacs.bioexcel.eu/u/maham)\
**Post date:** [August 15, 2024, 6:22pm UTC](https://gromacs.bioexcel.eu/t/error-in-hbond/9891/1 "2024-08-15T18:22:00Z")

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GROMACS version:  
GROMACS modification: Yes/No  
Here post your question  
I am trying to find whether 2 residues are making H-bond in the trajectory or not. I am selecting Threonine OG1 group and OD1 group of Aspartate but i am getting an error “Found 0 donors and 2 acceptors”.

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**Author:** ![jalemkul](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/jalemkul/32/18_2.png) [@jalemkul](https://gromacs.bioexcel.eu/u/jalemkul)\
**Post date:** [August 16, 2024, 2:10am UTC](https://gromacs.bioexcel.eu/t/error-in-hbond/9891/2 "2024-08-16T02:10:10Z")

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The donor group needs to include the H atom itself, e.g. HG1 of Thr.

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<div class="post-metadata">

**Author:** ![maham](https://avatars.discourse-cdn.com/v4/letter/m/c77e96/32.png) [@maham](https://gromacs.bioexcel.eu/u/maham)\
**Post date:** [August 19, 2024, 8:47am UTC](https://gromacs.bioexcel.eu/t/error-in-hbond/9891/3 "2024-08-19T08:47:37Z")

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Did that but the error said " Found 0 donors and 1 acceptors"  
I am trying one more thing where instead of selecting the specific atom i have selected the whole residue. is there a way where I can get the list of acceptor donor pair in the selection.  
i have tried the -o command but i keep getting error " Unknown command-line option -o"