Atomic physics and nuclear physics are two subfields of physics that focus on different aspects of matter at the atomic and nuclear level. While they both deal with atoms and nuclei, they have distinct areas of investigation and methodologies.
Atomic physics primarily studies the properties and behavior of atoms, which are composed of a nucleus (containing protons and neutrons) surrounded by electrons. It explores the interactions between electrons and the electromagnetic field, as well as the structure of atoms, their energy levels, and their spectroscopic properties. Atomic physics covers topics such as atomic spectra, atomic transitions, atomic collisions, and the interaction of atoms with external fields.
On the other hand, nuclear physics is concerned with the properties, structure, and behavior of atomic nuclei, which are composed of protons and neutrons. It investigates the forces that bind nucleons together within the nucleus, nuclear reactions and decays, nuclear structure, and nuclear energy levels. Nuclear physics involves the study of nuclear reactions, radioactive decay, nuclear fission, nuclear fusion, and the properties of unstable nuclei.
The distinction between atomic physics and nuclear physics arises from the differences in the scales and energies involved. Atomic physics primarily deals with the interactions of electrons with the electromagnetic force, which is typically on the order of electron volts (eV) and can be described by quantum mechanics. Nuclear physics, on the other hand, deals with the interactions between nucleons within the nucleus, which are governed by the strong nuclear force and require a description that includes both quantum mechanics and nuclear models.
While both atomic physics and nuclear physics involve the study of atoms and nuclei, they have different phenomena, energy scales, and experimental techniques associated with them. The separation of these fields allows researchers to focus on specific aspects of matter, develop specialized methodologies, and gain a deeper understanding of the behavior of atoms and nuclei. Additionally, the applications and technologies based on atomic and nuclear physics, such as atomic clocks, lasers, nuclear power, and medical imaging, require specialized knowledge from each field.