# How can I use Lennard-Jones and Buckingham Potential at the same time? **URL:** \ **Category:** User discussions\ **Created:** [January 16, 2025, 2:25pm UTC](https://gromacs.bioexcel.eu/t/how-can-i-use-lennard-jones-and-buckingham-potential-at-the-same-time/11052 "2025-01-16T14:25:46Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![Lois](https://avatars.discourse-cdn.com/v4/letter/l/5f8ce5/32.png) [@Lois](https://gromacs.bioexcel.eu/u/Lois)\ **Post date:** [January 16, 2025, 3:16pm UTC](https://gromacs.bioexcel.eu/t/how-can-i-use-lennard-jones-and-buckingham-potential-at-the-same-time/11052/2 "2025-01-16T15:16:42Z")
I think the way to do this (unless there is a simple way I haven’t come across, but this is good information to have anyway) would be to use tabulated potentials and then control the interactions between different energy groups in your .mdp file. See answers to this question on the forum: > [@Using tabulated potentials in gromacs](https://gromacs.bioexcel.eu/t/using-tabulated-potentials-in-gromacs/1753/3): > > @alevilla thank you for your response! So that is exactly what I have done. What I am wondering about is, what should my value of k (Boltzmann’s constant) be? Plugging in 1.38e-23 seems incorrect. How do the units work? For example, in the 6-9 LJ fluid, they simply plug in 1/r^9 in the C12 column. 1/r^9 has units of 1/(nm)^9, but the units of C12 is 4epsilonsigma^12 has units of kJ/mol(nm)^12 --- _[View the full topic](https://gromacs.bioexcel.eu/t/how-can-i-use-lennard-jones-and-buckingham-potential-at-the-same-time/11052)._