[lammps-users] request

Dear LAMMPS user,
I am going to simulate in system with 100 Benzene molecules. I want to use a angle potential consist of two terms: a harmonic term and a cubic term.
E=K1*(x1-x0)(x1-x0) - K2(x1-x0)(x1-x0)(x1-x0)
Is this potential function exist in the LAMMPS potential functions?
Thank you,
Hadi