Lecture

Atoms and Radiation: Lineshapes

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In course

CH-360: Atoms and radiation

This course discusses the interaction between atoms and visible electro-magnetic radiation and introduces the main instrumentation for light detection and spectroscopy. The principles of LASER light sources are described, providing notions of nonlinear and ...

Description

This lecture covers the concept of lineshapes in atoms and radiation, focusing on topics such as linewidths of spectral lines, lifetime broadening, natural linewidth, damping, Lorentzian lineshape, and broadening mechanisms. The instructor explains the physical origins of spectral line broadening, including contributions from monochromatic radiation, instrumental broadening, and damping terms. Various mechanisms such as Lorentzian lineshape, Voigt profile, and Doppler broadening are discussed in detail, along with examples from different laser materials. The lecture also delves into the effects of elastic and inelastic collisions on lineshapes, emphasizing the importance of understanding these phenomena in the study of atomic and radiation physics.

Official source

Related concepts (32)

Inelastic collision

An inelastic collision, in contrast to an elastic collision, is a collision in which kinetic energy is not conserved due to the action of internal friction. In collisions of macroscopic bodies, some kinetic energy is turned into vibrational energy of the atoms, causing a heating effect, and the bodies are deformed. The molecules of a gas or liquid rarely experience perfectly elastic collisions because kinetic energy is exchanged between the molecules' translational motion and their internal degrees of freedom with each collision.

Elastic collision

In physics, an elastic collision is an encounter (collision) between two bodies in which the total kinetic energy of the two bodies remains the same. In an ideal, perfectly elastic collision, there is no net conversion of kinetic energy into other forms such as heat, noise, or potential energy. During the collision of small objects, kinetic energy is first converted to potential energy associated with a repulsive or attractive force between the particles (when the particles move against this force, i.e.

Collision

In physics, a collision is any event in which two or more bodies exert forces on each other in a relatively short time. Although the most common use of the word collision refers to incidents in which two or more objects collide with great force, the scientific use of the term implies nothing about the magnitude of the force. In physics, collisions can be classified by the change in the total kinetic energy of the system before and after the collision: If most or all of the total kinetic energy is lost (dissipated as heat, sound, etc.

Spectral line

A spectral line is a weaker or stronger region in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules. These "fingerprints" can be compared to the previously collected ones of atoms and molecules, and are thus used to identify the atomic and molecular components of stars and planets, which would otherwise be impossible.

Radiation hardening

Radiation hardening is the process of making electronic components and circuits resistant to damage or malfunction caused by high levels of ionizing radiation (particle radiation and high-energy electromagnetic radiation), especially for environments in outer space (especially beyond the low Earth orbit), around nuclear reactors and particle accelerators, or during nuclear accidents or nuclear warfare.

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