Quantum Numbers

Quantum numbers describe values of conserved quantities in the dynamics of a quantum system. In the case of quantum numbers of electrons, they can be defined as "The sets of numerical values which give acceptable solutions to theSchrödinger wave equation for the Hydrogen atom". Perhaps the most important aspect of quantum mechanics is thequantization of observable quantities, since quantum numbers are discrete sets of integers or half-integers, although they could approach infinity in some cases. This is distinguished from classical mechanics where the values can range continuously. Quantum numbers often describe specifically the energy levels of electrons in atoms, but other possibilities include angular momentum, spin, etc. Any quantum system can have one or more quantum numbers; it is thus difficult to list all possible quantum numbers.

There are four quantum numbers which can describe the electron completely.

• Principal quantum number (n)
• Azimuthal quantum number (ℓ)
• Magnetic quantum number (m)
• Spin quantum number (s)

The principal quantum number (n) describes the electron shell, or energy level, of an atom. The value of n ranges from 1 to the shell containing the outermost electron of that atom.

The azimuthal quantum number (ℓ) (also known as the angular quantum number or orbital quantum number) describes the subshell, and gives the magnitude of the orbital angular momentum.

The magnetic quantum number (m_ℓ) describes the specific orbital (or "cloud") within that subshell, and yields the projection of the orbital angular momentum along a specified axis.

The spin projection quantum number (m_s) describes the spin (intrinsic angular momentum) of the electron within that orbital, and gives the projection of the spin angular momentum S along the specified axis. An electron has spin s = ½, consequently m_s will be ±½, corresponding with "spin" and "opposite spin." Each electron in any individual orbital must have different spins because of the Pauli exclusion principle, therefore an orbital never contains more than two electrons.

Name	Symbol	Orbital meaning	Range of values	Value examples
principal quantum number	n	shell	1 ≤ n	n = 1, 2, 3, …
azimuthal quantum number (angular momentum)	ℓ	subshell (s orbital is listed as 0, p orbital as 1 etc.)	0 ≤ ℓ ≤ n − 1	for n = 3: ℓ = 0, 1, 2 (s, p, d)
magnetic quantum number, (projection ofangular momentum)	mℓ	energy shift (orientation of the subshell's shape)	−ℓ ≤ mℓ ≤ ℓ	for ℓ = 2: mℓ = −2, −1, 0, 1, 2
spin projection quantum number	ms	spin of the electron (−½ = "spin down", ½ = "spin up")	−s ≤ ms ≤ s	for an electron s = ½, so ms = −½, ½

Source: http://en.wikipedia.org/wiki/Quantum_number

Another recommended reading: http://skullsinthestars.com/2008/05/27/the-gallery-of-failed-atomic-models-1903-1913/

Solar Flares gives antimatter

Erupção solar captada pela SOHO em 28 de outubro de 2003 (NASA / SOHO)

Associated with solar magnetic storms, solar flares are giant explosions on the sun that send energy, light and particles in all directions to the space. Their number increases approximately every 11 years.

When the universe was formed 13.8 billion years ago in the event known as the Big Bang, there was the same amount of matter and antimatter. Somehow the matter antimatter annihilated (when matter and antimatter meet, they annihilate each other), leaving only a portion of matter, enough to form stars, planets and galaxies that make up our universe.

The study of natural sources of antimatter, will allow researchers to understand why antimatter lost the battle to matter in the beginning of our universe.

Positrons are antiparticles of the antimatter. The positron, e⁺, and electrons, e^-, (populating the common atoms) have the same physical behavior, except that the electrons have a negative charge while the positrons, as its name indicates, have a positive charge. This charge's difference causes that positrons interact differently with electromagnetic fields, which Professor Gregory Fleishman, from the New Jersey Institute of Technology and his colleagues from the Russia's Institute of Solar-Terrestrial Physics used to distinguish them.

The process of solar flares are very energetic and the ejected mass accelerates particles to speeds approaching the speed of light, allowing the creation of these positrons.

Using data from SOHO and radio images of two different frequencies obtained from Japan's Nobeyama Radioheliograph, the Russian-American team found that the light was polarized in different directions for low frequencies, where the ordinary matter dominates, compared to higher frequencies where antimatter is more expected.

"That this kind of antiparticles are created in solar flares is not surprising, but this is the first time that the immediate effects are detected," these results were presented on July 8, at the 44th meeting of Society American Astronomical Society's Solar Physics Division of the Bozeman, Montana.

The study has profound implications for obtaining valuable knowledge through remote sensing antiparticles relativistic starting the Sun and possibly other astrophysical objects through observations of radio telescopes.

Sources: sci-news, space.com, dailygalaxy