Each orbital is defined by a different set of quantum numbers ( n, l, and m ), and contains a maximum of two electrons each with their own spin quantum number.

All elementary particles have a characteristic spin, for example electrons always have " spin 1 / 2 " while photons always have " spin 1 ".

Although there are no known magnetic monopoles in nature, there are magnetic dipoles in the form of the quantum-mechanical spin associated with particles such as electrons ( although the accurate description of such effects falls outside of classical electromagnetism ).

In laboratory conditions, the interactions of individual electrons can be observed by means of particle detectors, which allow measurement of specific properties such as energy, spin and charge.

* Electron spin resonance or electron paramagnetic resonance, a technique used in chemical spectroscopy to identify unpaired electrons and free radicals

A source ( center ) sends particles toward two observers, electrons to Alice ( left ) and positrons to Bob ( right ), who can perform spin measurements.

This is the origin of superconductivity and the superfluidity of helium-3: in superconducting materials, electrons interact through the exchange of phonons, forming Cooper pairs, while in helium-3, Cooper pairs are formed via spin fluctuations.

Because of Hund's rules, the first few electrons in a shell tend to have the same spin, thereby increasing the total dipole moment.

In a few materials, a much stronger interaction between spins arises because the change in the direction of the spin leads to a change in electrostatic repulsion between neighboring electrons, due to a particular quantum mechanical effect called the exchange interaction.

The exchange interaction is related to the Pauli exclusion principle, which says that two electrons with the same spin cannot also have the same " position ".

This symmetry reflects similar underlying physics: the pair of neutrons and the pair of protons in helium's nucleus obey the same quantum mechanical rules as do helium's pair of electrons ( although the nuclear particles are subject to a different nuclear binding potential ), so that all these fermions fully occupy 1s orbitals in pairs, none of them possessing orbital angular momentum, and each cancelling the other's intrinsic spin.

The quantum mechanical effects on helium-3 and helium-4 are significantly different because with two protons, two neutrons, and two electrons, helium-4 has an overall " spin " of zero, making it a boson, but with one fewer neutron, helium-3 has an overall spin of plus or minus one half, making it a fermion.

It proposes that electrons with opposite spin can become paired, forming Cooper pairs.

In the case of two electrons occupying the same orbital, the Pauli principle demands that they have opposite spin.

While paired electrons are required by the Pauli exclusion principle to have their intrinsic (' spin ') magnetic moments pointing in opposite directions, causing their magnetic fields to cancel out, an unpaired electron is free to align its magnetic moment in any direction.

In contrast, the Coulomb repulsion of the electrons, i. e. the tendency that they try to avoid each other by this repulsion, would lead to an antisymmetric orbital function ( i. e. with the-sign ) of these two particles, and complementary to a symmetric spin function ( i. e. with the + sign, one of the so-called " triplet functions ").

For d-and especially f-electrons the delocalization is not strong at all and this explains why these electrons are able to continue behaving as unpaired electrons that retain their spin, adding interesting magnetic properties to these metals.

By 1925 it was known that protons and electrons had a spin of 1 / 2, and in the Rutherford model of nitrogen-14, 20 of the total 21 nuclear particles should have paired up to cancel each other's spin, and the final odd particle should have left the nucleus with a net spin of 1 / 2.

When a beam of silver atoms was passed through a specially shaped magnetic field, the beam was split based on the direction of an atom's angular momentum, or spin.

In order to obtain exact agreement with experiment, it is necessary to include relativistic and spin orbit terms, both of which are only really important for heavy atoms.

If a sample of cobalt-60 atoms is magnetized so that they spin counterclockwise around some axis, the beta radiation resulting from their nuclear decay will be preferentially directed opposite that axis.

Since counter-clockwise may be defined in terms of up, forward, and right, this experiment unambiguously differentiates left from right using only natural elements: If they were reversed, or the atoms spun clockwise, the radiation would follow the spin axis instead of being opposite to it.

At standard temperature and pressure, oxygen is a very pale blue, odorless gas with the molecular formula, in which the two oxygen atoms are chemically bonded to each other with a spin triplet electron configuration.

* Fullerene-based ESR quantum computer ( qubit based on the electronic spin of atoms or molecules encased in fullerene structures )

Transition metal atoms often have magnetic moments due to the net spin of electrons that remain unpaired and do not form chemical bonds.

When in a normal solid state, the atoms of matter align themselves in a grid pattern, so that the spin of any electron is the opposite of the spin of all electrons touching it.

But in a string-net liquid, atoms are arranged in some pattern that requires some electrons to have neighbors with the same spin.

While antihydrogen atoms are electrically neutral, their spin produces magnetic moments.

He developed techniques for using nuclear magnetic resonance to discern the magnetic moment and nuclear spin of atoms.

Thus, atoms that are in close proximity to each other can give a NOE, whereas spin coupling is observed only when the atoms are connected by 2 – 3 chemical bonds.

In this case, energy flows fairly rapidly among the spin states of interacting atoms, but energy transfer between the nuclear spins and other modes is relatively slow.

Quantum numbers often describe specifically the energies of electrons in atoms, but other possibilities include angular momentum, spin, etc.

Then the natural assumption, given that all atoms are detected, is that all atoms the projection of whose spin in the direction a is positive will be detected as spin up ( coded as + 1 ) while all whose projection is negative will be detected as spin down ( coded as − 1 ).

* Hyperpolarization ( physics ) is the selective polarization of nuclear spin in atoms far beyond normal thermal equilibrium

The total spin of the helium-4 nucleus is an integer ( zero ), and therefore it is a boson ( as are neutral atoms of helium-4 ).

The input axis of the X gyro, when pointing in the east-west direction, is always perpendicular to the spin axis of earth.

In particle physics, antimatter is material composed of antiparticles, which have the same mass as particles of ordinary matter but have opposite charge and quantum spin.

If denotes the quantum state of a particle ( n ) with momentum p, spin J whose component in the z-direction is σ, then one has

In orbits, the angular momentum is distributed between the spin of the planet itself and the angular momentum of its orbit:

Angular momenta of a classical object .< p > Left: intrinsic " spin " angular momentum S is really orbital angular momentum of the object at every point ,</ p >< p > right: extrinsic orbital angular momentum L about an axis ,</ p >< p > top: the moment of inertia tensor | moment of inertia tensor I and angular velocity ω ( L is not always parallel to ω )</ p >< p > bottom: momentum p and it's radial position r from the axis .</ p > The total angular momentum ( spin + orbital ) is J.

However, in quantum physics, there is another type of angular momentum, called spin angular momentum, represented by the spin operator S. Almost all elementary particles have spin.

Finally, there is total angular momentum J, which combines both the spin and orbital angular momentum of all particles and fields.

Natural beryllium, save for slight contamination by cosmogenic radioisotopes, is essentially beryllium-9, which has a spin of-3 / 2.

A boomerang is a thrown tool, typically constructed as a flat aerofoil, that is designed to spin about an axis perpendicular to the direction of its flight.

The result of the efforts of Bose and Einstein is the concept of a Bose gas, governed by Bose – Einstein statistics, which describes the statistical distribution of identical particles with integer spin, now known as bosons.

where is the state with a definite value of the spin operator S < sub > z </ sub > equal to + 1 / 2 and is the state with a definite value of the spin operator S < sub > z </ sub > equal to-1 / 2.

If the cord is twisted up tightly on itself and then the bucket is released, it begins to spin rapidly, not only with respect to the experimenter, but also in relation to the water it contains.