From my perspective, the General Amber Force Field (GAFF) primarily utilizes the Lennard-Jones 12-6 potential parameters for both bonded and non-bonded interactions. This choice is consistent with typical force field parameterization for organic molecules. The 12-6 potential represents the van der Waals interactions between atoms, with the 12 term governing the repulsive part and the 6 term governing the attractive part of the potential energy function.

In GAFF, these parameters are derived from a combination of quantum mechanical calculations and experimental data to accurately represent the behavior of organic molecules in various environments. Therefore, your assumption that GAFF uses Lennard-Jones 12-6 potential parameters for both bonded and non-bonded interactions is correct. Hopefully, this clarification aids in your understanding.

Hopefully, the article below will help you gain a better understanding.

Wang, Junmei, et al. "Development and testing of a general amber force field." Journal of computational chemistry 25.9 (2004): 1157-1174.

Thanks a lot Md Masuduzzaman

I have got my clarification about this.