# What are the selection rules for the emission of gamma rays?

## What are the selection rules for the emission of gamma rays?

The selection rules for γ-ray decay result from the laws of conservation of angular momentum and parity. A photon from the decay carries out an angular momentum of L and parity π.

## What is meant by multipole radiation?

Multipole radiation is a theoretical framework for the description of electromagnetic or gravitational radiation from time-dependent distributions of distant sources. Electromagnetic radiation depends on structural details of the source system of electric charge and electric current.

## What is magnetic radiation and electric gamma decay?

A gamma ray, also known as gamma radiation (symbol γ or. ), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically shorter than those of X-rays.

## Which of the choices is a characteristic of gamma radiation?

Because it is electromagnetic radiation, gamma photons have no mass and no electrical charge, and they travel at the speed of light (3.108 m.s-1), being able to cover hundreds to thousands of meters in air before spending their energy.

## What is the spin selection rule?

Spin Selection Rule: The overall spin S of a complex must not change during an electronic transition, hence, ΔS = 0.

## Why do we need multipole expansion?

A multipole expansion is a mathematical series representing a function that depends on angles—usually the two angles on a sphere. These series are useful because they can often be truncated, meaning that only the first few terms need to be retained for a good approximation to the original function.

## What is multipole expansion of charge distribution?

In physics, the electric potential Φ, caused by—and outside—a non-central-symmetric charge distribution ρ(r), can be expanded in a series, the multipole expansion of Φ. This expansion is in terms of powers of 1/R, where R is the distance of a field point R to a point inside ρ.

## Why can gamma rays penetrate almost all matter?

Gamma rays are detected by their ability to ionize gas atoms or to create electron–hole pairs in semiconductors or insulators. The great penetrating power of gamma rays stems from the fact that they have no electric charge and thus do not interact with matter as strongly as do charged particles.

## How does gamma radiation decay?

gamma decay, type of radioactivity in which some unstable atomic nuclei dissipate excess energy by a spontaneous electromagnetic process. In internal conversion, excess energy in a nucleus is directly transferred to one of its own orbiting electrons, thereby ejecting the electron from the atom. …

## What are the positive effects of gamma rays?

Because Gamma rays can kill living cells, they are used to kill cancer cells without having to resort to difficult surgery. This is called “Radiotherapy”, and works because healthy cells can repair themselves fairly well when damaged by gamma rays – but cancer cells can’t.

## How are gamma rays used in everyday life?

Gamma rays are used in medicine (radiotherapy), industry (sterilization and disinfection) and the nuclear industry. Shielding against gamma rays is essential because they can cause diseases to skin or blood, eye disorders and cancers.

## What are the selection rules for the electric dipole approximation?

The above selection rules apply only for the Electric Dipole (E1) approximation. Higher order terms in the expansion, like the Electric Quadrupole (E2) or the Magnetic Dipole (M1), allow other decays but the rates are down by a factor of or more.

## Is there an absolute selection rule for photon decay rate?

There is one absolute selection rule coming from angular momentum conservation, since the photon is spin 1. No to transitions in any order of approximation. As a summary of our calculations in the Electric Dipole approximation, lets write out the decay rate formula.

## What does the electromagnetic field from a multipole moment depend on?

The field from a multipole moment depends on both the distance from the origin and the angular orientation of the evaluation point with respect to the coordinate system. In particular, the radial dependence of the electromagnetic field from a stationary

## What is the application of integrand in magnetic dipole?

Application to a pure electric dipole gives . Integration over a sphere yields the total power radiated: , applied to the vector potential gives magnetic dipole radiation and electric quadrupole radiation. The integrand can be separated into symmetric and anti-symmetric parts in J and x ′ and integration gives the magnetic dipole moment.