# Radial density profile issue

**URL:** <https://gromacs.bioexcel.eu/t/radial-density-profile-issue/11534>\
**Category:** User discussions\
**Created:** [February 12, 2025, 1:44pm UTC](https://gromacs.bioexcel.eu/t/radial-density-profile-issue/11534 "2025-02-12T13:44:11Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Narges](https://avatars.discourse-cdn.com/v4/letter/n/7993a0/32.png) [@Narges](https://gromacs.bioexcel.eu/u/Narges)\
**Post date:** [February 12, 2025, 1:44pm UTC](https://gromacs.bioexcel.eu/t/radial-density-profile-issue/11534/1 "2025-02-12T13:44:12Z")

</div>

GROMACS version:2022.3  
GROMACS modification: Yes/No  
Hi all,

I have simulated a polymer nanosphere nanocomposite system. In my setup, the nanoparticle is positioned in the center, and the polymer chains are distributed around it. The system has been well-equilibrated.

However, when I use the following command to calculate the radial density:

gmx density -f NPT.trr -s NPT.tpr -center -o radialdensity.xvg

The resulting radial density profile is not smooth. I tried increasing the temperature, but the issue persists.

Could anyone help me identify the possible reasons for this issue and suggest how to address it?

 ![Screenshot from 2025-02-12 16-49-00](https://europe1.discourse-cdn.com/flex017/uploads/bioexcel1/original/2X/5/55a0863242c1d38a90de147ba5739e42cac475d3.png)