Short- and Long-Range Interatomic Forces

There are different types of forces that make up the interaction between two atoms over a large range of separation. Both experimental phenomena and theoretical considerations suggest that the forces can be categorized as short- and long-range forces. 

If one or both of the particles are neutral, this Coulomb force is zero in the two-body approximation, and the long-range interaction is greatly reduced. 

As two atoms approach each other, some degree of merging of the particles occurs. As the particles merge, the electron orbits from the electrons of each atom begin to overlap, and a limitation in the occupation of available electron states arises due to the Pauli Exclusion Principle. Under such circumstances, the 

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