In physics, one thinks of atomic spectral lines from two viewpoints.

These characteristic energy values, defined by the differences in the energies of the quantum states, are responsible for atomic spectral lines.

Like ferromagnetism and atomic spectral lines, superconductivity is a quantum mechanical phenomenon.

The final column gives the historical origin of the labels s, p, d, and f. They come from early studies of atomic spectral lines.

Atomic spectral line (deduction of the Einstein coefficients)

In 1916, Albert Einstein proposed that there are three processes occurring in the formation of an atomic spectral line.

This allows all three Einstein coefficients to be expressed in terms of the single oscillator strength associated with the particular atomic spectral line:

Atomic spectral lines are due to transitions of electrons between different atomic energy levels E, followed by emission of photons.

It is usually called isomeric shift on atomic spectral lines and Mössbauer isomeric shift respectively.

Spectral lines are the result of interaction between a quantum system (usually atomic spectral line, but sometimes molecules or atomic nucleus) and a single photon.

In atomic physics, the atomic spectral lines correspond to transitions (quantum leaps) between quantum states of an atom.

Spectroscopic measurements of the strength and width of atomic spectral lines allow the composition and physical properties of a substance to be determined.

The isomeric shift on atomic spectral lines is the energy or frequency shift in atomic spectra, which occurs when one replaces one nuclear isomer by another.

The brightness of an atomic spectral line emitted by atoms in a gas (or plasma) can be proportional to the gas's temperature, pressure or a weighted sum of both.

These absorptions and emissions, often referred to as atomic spectral lines, are due to electronic transitions of outer shell electrons as they rise and fall from one electron orbit to another.

Arnold Sommerfeld introduced the fine-structure constant in 1916, as part of his theory of the relativistic deviations of atomic spectral lines from the predictions of the Bohr model.

The wavelength of the atomic spectral line gives the identity of the element while the intensity of the emitted light is proportional to the number of atoms of the element.

This is so because isotopes differ by the number of neutrons and therefore the masses and volumes of two isotopes are different; these differences give rise to the isotopic shift on atomic spectral lines.

The result of the calculation was that the isomeric shift on atomic spectral lines, although rather small, turned out to be two orders of magnitude bigger than a typical natural line width, which constitutes the limit of optical measurability.

Due to the completeness and accuracy of collisional radiative models for helium the temperature and density of plasmas which have helium present can be measured by taking ratios of the emission intensities of various atomic spectral lines.

Since atomic spectral lines were largely in the realm of physics and not in that of chemistry, most chemists were unfamiliar with relativistic quantum mechanics, and their attention was on lighter elements typical for the organic chemistry focus of the time.

An atomic spectral line refers to emission and absorption events in a gas in which is the density of atoms in the upper energy state for the line, and is the density of atoms in the lower energy state for the line.

Cutler, Leonard S. "New Series of Microwave Sweep Oscillators with Flexible Modulation and Leveling, by Robert L. Dudley Examination of the Atomic Spectral Lines of a Cesium Beam Tube with the -hp- Frequency Synthesizer."