Molecular Physics

Molecular physics studies molecules and the physical phenomena associated with them.  It focuses on the structure, motion, energy, interactions, and behavior of molecules, especially as governed by the laws of quantum mechanics, electromagnetism, thermodynamics, and statistical mechanics.  Molecular physics examines how atoms combine to form molecules and how those molecules behave individually and collectively under different physical conditions.

A molecule is a group of two or more atoms bound together by electromagnetic forces, primarily through chemical bonds.  Molecular physics investigates the physical properties of these systems rather than their chemical reactivity alone.  Because molecules exist at atomic and subatomic scales, their behavior cannot be fully explained by classical physics alone.  Quantum mechanics describes how electrons occupy quantized energy levels within molecules and how molecular bonds arise from electron interactions.