Atomic Recoil
Encyclopedia
Atomic recoil is the result of the interaction of an atom with an energetic elementary particle
, when the momentum
of the interacting particle is transferred to the atom
as whole without altering non-translational degrees of freedom of the atom. It is a purely quantum
phenomenon.
If the transferred momentum of atomic recoil is enough to disrupt the crystal lattice of the material, a vacancy defect is formed otherwise a phonon
is generated.
Closely related to the atomic recoil is the electron recoil, (see photoexcitation and photoionization).
Another form is the nuclear recoil, when momentum transfers to the atomic nucleus
as whole.
In some cases quantum effects can forbid momentum transfer to an individual nucleus, and momentum is transferred to the crystal lattice as a whole. (see Mössbauer effect
)
Elementary particle
In particle physics, an elementary particle or fundamental particle is a particle not known to have substructure; that is, it is not known to be made up of smaller particles. If an elementary particle truly has no substructure, then it is one of the basic building blocks of the universe from which...
, when the momentum
Momentum
In classical mechanics, linear momentum or translational momentum is the product of the mass and velocity of an object...
of the interacting particle is transferred to the atom
Atom
The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...
as whole without altering non-translational degrees of freedom of the atom. It is a purely quantum
Quantum mechanics
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...
phenomenon.
If the transferred momentum of atomic recoil is enough to disrupt the crystal lattice of the material, a vacancy defect is formed otherwise a phonon
Phonon
In physics, a phonon is a collective excitation in a periodic, elastic arrangement of atoms or molecules in condensed matter, such as solids and some liquids...
is generated.
Closely related to the atomic recoil is the electron recoil, (see photoexcitation and photoionization).
Another form is the nuclear recoil, when momentum transfers to the atomic nucleus
Atomic nucleus
The nucleus is the very dense region consisting of protons and neutrons at the center of an atom. It was discovered in 1911, as a result of Ernest Rutherford's interpretation of the famous 1909 Rutherford experiment performed by Hans Geiger and Ernest Marsden, under the direction of Rutherford. The...
as whole.
In some cases quantum effects can forbid momentum transfer to an individual nucleus, and momentum is transferred to the crystal lattice as a whole. (see Mössbauer effect
Mössbauer effect
The Mössbauer effect, or recoilless nuclear resonance fluorescence, is a physical phenomenon discovered by Rudolf Mössbauer in 1958. It involves the resonant and recoil-free emission and absorption of γ radiation by atomic nuclei bound in a solid...
)