Repulsion occurs as each particle attempts to retain the space in their respective orbitals. Despite the repulsive force between both particles, their bonding potential energy increases rapidly as the distance of separation decreases.

Does repulsion increase or decrease energy?

As the atoms near each other, their outer (valence) electrons interact to repel each other, and this repulsion energy increases very rapidly as the distance r decreases. ... This increase in energy as atoms are crowded together is called steric repulsion or steric hindrance.

Why does a repulsive force increase potential energy?

Because of the electrostatic force of attraction or repulsion between them, two charged particles will vary in energy as we alter the distance between them. Opposite (+ and -) charges attract, just like the earth and any object, so the potential energy increases as we put effort in to separate the charges.