# Polarisation in itp file **URL:** \ **Category:** User discussions\ **Created:** [July 11, 2022, 5:01am UTC](https://gromacs.bioexcel.eu/t/polarisation-in-itp-file/4450 "2022-07-11T05:01:31Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![hema](https://avatars.discourse-cdn.com/v4/letter/h/258eb7/32.png) [@hema](https://gromacs.bioexcel.eu/u/hema)\ **Post date:** [July 11, 2022, 5:01am UTC](https://gromacs.bioexcel.eu/t/polarisation-in-itp-file/4450/1 "2022-07-11T05:01:31Z")
Dear Gromacs Users, I am doing simulation using Gromacs software. I want to add polarisation in itp file. Here I found format of polarisation in itp file. [polarization] ; Atom i j type alpha 1 2 1 0.001 But I am confused what is atom, i, j here and how they take. Can anyone help me regarding this. Thank you very much in advanced for your kind help. Regards Hema Teherpuria