Reviewing the Morse potential
In this section, we analyze the Morse potential implemented by the pair_morse.cpp and pair_morse.h classes.
The Morse potential (
) is used to represent the covalent character of bonds and consists of a repulsive and an attractive part with a potential minimum in between. The functional form of the Morse potential is given by the following:
From the preceding equation, 
represents the depth of the Morse potential well, 
determines the curvature of the well, and 
represents the equilibrium distance. In a LAMMPS input script, the Morse pair potential is implemented using the following commands:
pair_style morse GLOBAL_CUTOFF pair_coeff TYPE1 TYPE2 D0 ALPHA R0 LOCAL_CUTOFF
From the preceding code, D0, ALPHA, R0 are the three Morse parameters described, and the GLOBAL_CUTOFF and LOCAL_CUTOFF parameters are the cutoffs used for all atom pairs or specified atom pairs, respectively...
