# How to add Cadmium parameters in amber OL15 nucleic forcefield?

**URL:** <https://gromacs.bioexcel.eu/t/how-to-add-cadmium-parameters-in-amber-ol15-nucleic-forcefield/4164>\
**Category:** User discussions\
**Tags:** forcefield\
**Created:** [May 14, 2022, 9:30am UTC](https://gromacs.bioexcel.eu/t/how-to-add-cadmium-parameters-in-amber-ol15-nucleic-forcefield/4164 "2022-05-14T09:30:57Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![reza786](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@reza786](https://gromacs.bioexcel.eu/u/reza786)\
**Post date:** [May 14, 2022, 9:30am UTC](https://gromacs.bioexcel.eu/t/how-to-add-cadmium-parameters-in-amber-ol15-nucleic-forcefield/4164/1 "2022-05-14T09:30:57Z")

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GROMACS version: 2021.4  
GROMACS modification: Yes/No  
Dear all, I am using OL15 amber forcefield for my DNAzyme molecule and I need to add Cd2+ ion instead of Mg2+ ion. In OL15 forcefield there are no parameters for Cadmium ion. Now, I want to know how to add Cadmium ions parameters in this forcefield and then use them in my MD simulation.