Atomic Physics
Atomic Physics - Related Videos
09:10
Construction and Characterization of External Cavity Diode Lasers for Atomic Physics
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Cited by 5 •
2014
This is an instructional paper to guide the construction and diagnostics of external cavity diode lasers (ECDLs), including component selection and optical alignment, as well as the basics of frequency reference spectroscopy and laser linewidth measurements for applications in the field of atomic physics.
01:33
Atomic Structure
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2026
All matter is composed of atoms, the smallest individual units of elements. Each atom is made up of three subatomic particles: protons, neutrons, and electrons. Together, these three particles account for the mass and the charge of an atom.The History of Atomic TheoryThe first person to propose that everything on Earth is made up of tiny particles was the Greek philosopher Democritus, around 450 B.C. He used the term atomos, Greek for “indivisible,” from which the modern term “atom” is derived.
02:57
Physical and Chemical Properties of Matter
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2020
The characteristics that enable us to distinguish one substance from another are called properties. Physical Properties of Matter A physical property is a characteristic of matter that is not associated with a change in its chemical composition. Familiar examples of physical properties include density, color, hardness, melting and boiling points, and electrical conductivity. We can observe some physical properties, such as density and color, without changing the physical state of the matter...
05:51
Atomic Force Microscopy to Study the Physical Properties of Epidermal Cells of Live Arabidopsis Roots
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Cited by 1 •
2022
The atomic force microscopy indentation protocol offers the possibility to dissect the role of the physical properties of the cell wall of a particular cell of a tissue or organ during normal or constrained growth (i.e., under water deficit).
01:52
Atomic Mass
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2020
Atoms — and the protons, neutrons, and electrons that compose them — are extremely small. For example, a carbon atom weighs less than 2 × 10−23 g. When describing the properties of tiny objects such as atoms, we use appropriately small units of measure, such as the atomic mass unit (amu). The amu was originally defined based on hydrogen, the lightest element, then later in terms of oxygen. Since 1961, it has been defined with regard to the most abundant isotope of carbon, atoms of which are...
FAQs
An electron can move between discrete energy states only by exchanging a photon whose energy matches the difference between those states. A larger energy difference corresponds to a higher-energy photon, while a smaller difference corresponds to a lower-energy photon. Because photon energy is linked to wavelength, these transitions produce characteristic spectral features that identify atomic behavior.
External electromagnetic fields interact with the properties of electrons and atoms, changing the energies of otherwise distinct states. A field can shift a level or separate states that previously had the same energy, producing measurable changes in transition frequencies. Atomic physics uses these effects to study field interactions and to support highly precise measurements.
Atomic physics describes electrons with quantum mechanics, in which allowed energies occur as discrete states rather than as any continuous value. This framework explains why atoms absorb or emit photons at particular energies and why electromagnetic fields can alter spectral structure. Classical descriptions alone do not provide this account of discrete atomic behavior.
Spectroscopy examines the photons atoms absorb or emit during transitions between energy states. The resulting spectral features provide information about the underlying energy structure and about changes caused by electromagnetic fields. In practice, this makes spectroscopy a way to investigate atomic properties through measurable light signals rather than by observing electron motion directly.
Laser development depends on controlling atomic energy states and the photon transitions associated with them. Atomic physics supplies the framework for understanding how atoms interact with light and electromagnetic fields, allowing those interactions to be used in a controlled way. This connection makes atomic behavior relevant to technologies that generate and manage laser light.
Atomic clocks and precision measurements rely on the stability and reproducibility of atomic transitions. Since atoms possess discrete energy states, their transition-related frequencies can serve as consistent references. Studying how fields shift or split those states is important because such effects influence the interpretation and control of highly precise measurements.