How can I modify Morse potential using linear combinations of Gaussian functions

hello everyone,
I am learning how to use Lammps. I found a Ni-He potential function is proposed in the literature. I want to write the Ni-He potential function according to the author’s description for the following simulation. How can linear combinations of gaussian functions be written in lammps ?I tried to write the potential function presented in the paper according to my understanding, which is shown in Figure 2. Is there anyone who has made similar modifications? Could you help me solve this problem?
Thank you!

Ref:《Atomistic simulations and experimental measurements of helium nano-bubbles in nickel》

You need the source code from the authors of the paper or you need to implement this in C++ yourself.

You may be able to use pair_style lepton to implement that potential without C++ programming at a performance penalty.

Your hybrid pair style is completely bogus as a matter of principle.