# Optimal Trajectory Saving for Accurate H-bond Lifetime Calculation

**URL:** https://gromacs.bioexcel.eu/t/optimal-trajectory-saving-for-accurate-h-bond-lifetime-calculation/8034
**Category:** User discussions
**Tags:** mdp-parameters, analysis-tools, simulation-setup
**Created:** [January 14, 2024, 5:28am UTC](https://gromacs.bioexcel.eu/t/optimal-trajectory-saving-for-accurate-h-bond-lifetime-calculation/8034 "2024-01-14T05:28:22Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![ehsan](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/ehsan/32/1345_2.png) [@ehsan](https://gromacs.bioexcel.eu/u/ehsan)
#### Post date: [January 14, 2024, 5:28am UTC](https://gromacs.bioexcel.eu/t/optimal-trajectory-saving-for-accurate-h-bond-lifetime-calculation/8034/1 "2024-01-14T05:28:22Z")

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Dear all,

For calculating the hbond lifetime in a trajectory (.xtc) using gmx hbond with the -ac flag, is it necessary to save the trajectory in very short increments (e.g., 10 ps) for more accurate results?

Is there a specific limit on saving trajectory to ensure accuracy?

Kind regards,

Ehsan