independent-particle model

The independent-particle model in physics posits that individual particles within a system, such as protons and neutrons in an atomic nucleus, interact minimally with each other. Each particle is treated as moving in its own orbit within an average field created by the others, rather than being strongly coupled to them. This approach simplifies complex systems by focusing on individual particle behavior, contrasting with models where particles are assumed to interact cooperatively due to strong forces.1

This model is foundational in understanding atomic structure, particularly in the context of quantum mechanics. For instance, in multielectron atoms, the behavior of electrons is approximated by considering each electron in an average electric field, leading to the concept of orbitals. The Pauli exclusion principle, which states that no two identical fermions can occupy the same quantum state, is a crucial consequence of the antisymmetric wave functions required for such particles and underpins many properties of matter.2