FACTOID # 61: The average woman in New Zealand doesn't give birth until she is nearly 30 years old.
 
 Home   Encyclopedia   Statistics   Countries A-Z   Flags   Maps   Education   Forum   FAQ   About 
 
WHAT'S NEW
RECENT ARTICLES
More Recent Articles »
 

SEARCH ALL

FACTS & STATISTICS   

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Azimuthal quantum number

The Azimuthal quantum number (or orbital angular momentum quantum number) symbolized as l (lower-case L) is a quantum number for an atomic orbital which determines its orbital angular momentum. The azimuthal quantum number is the second of a set of quantum numbers (the principal quantum number, following Spectroscopic notation, the azimuthal quantum number, the magnetic quantum number, and the spin quantum number) which describe the unique quantum state of an electron and is designated by the letter l. A quantum number describes the energies of electrons in atoms. ... In chemistry, an atomic orbital is the region in which an electron may be found around a single atom. ... This gyroscope remains upright while spinning due to its angular momentum. ... In atomic physics, the principal quantum number symbolized as n is the first quantum number of an atomic orbital. ... Before the atom electron states were known, spectroscopists saw distinctive series in atom spectra, and so they assigned letters to characteristic spectra. ... By virtue of its charge and spin motion, an electron develops a magnetic field. ... In atomic physics, the spin quantum number is a quantum number that parametrizes the intrinsic angular momentum (or spin angular momentum, or simply spin) of a given particle. ... A quantum state is any possible state in which a quantum mechanical system can be. ...

Contents

Derivation

There is a set of quantum numbers associated with the energy states of the atom. The four quantum numbers n, l, ml, and s specify the complete and unique quantum state of a single electron in an atom called its wavefunction or orbital. The wavefunction of the Schrödinger wave equation reduces to the three equations that when solved lead to the first three quantum numbers. Therefore, the equations for the first three quantum numbers are all interrelated. The azimuthal quantum number arose in the solution of the polar part of the wave equation as shown below. A quantum state is any possible state in which a quantum mechanical system can be. ... This article discusses the concept of a wavefunction as it relates to quantum mechanics. ... In chemistry, an atomic orbital is the region in which an electron may be found around a single atom. ... In physics, the Schrödinger equation, proposed by the Austrian physicist Erwin Schrödinger in 1925, describes the time-dependence of quantum mechanical systems. ...


An atomic electron's angular momentum, L, which is related to its quantum number mathbf{}l is described by the following equation: This gyroscope remains upright while spinning due to its angular momentum. ...

mathbf{L^2boldsymbol{psi}} = hbar^2{l(l+1)}boldsymbol{psi}

where hbar = h/2pi is the reduced Planck's constant, also called Dirac's constant, mathbf{L^2} is the orbital angular momentum operator and boldsymbol{psi} is the wavefunction of the electron. While many introductory text books on quantum mechanics will refer to L by itself, L has no real meaning except in its use as the angular momentum operator. When referring to angular momentum, it is best to simply use the quantum number l,. A commemoration plaque for Max Planck on his discovery of Plancks constant, in front of Humboldt University, Berlin. ... In mathematics, an operator is a function that performs some sort of operation on a number, variable, or function. ...


The energy of any wave is the frequency multiplied by Planck's constant. This causes the wave to display particle-like packets of energy called quanta. To show each of the quantum numbers in the quantum state, the formulae for each quantum number include Planck's reduced constant which only allows particular or discrete or quantized energy levels. In physics quanta is the plural of quantum. ...


This behavior manifests itself as the "shape" of the orbital.

The atomic orbital wavefunctions of a hydrogen atom. The principal quantum number is at the right of each row and the azimuthal quantum number is denoted by letter at top of each column.
The atomic orbital wavefunctions of a hydrogen atom. The principal quantum number is at the right of each row and the azimuthal quantum number is denoted by letter at top of each column.

Electron shells have distinctive shapes denoted by letters. In the illustration, the letters s, p, and d describe the shape of the atomic orbital. Image File history File links HAtomOrbitals. ... In chemistry, an atomic orbital is the region in which an electron may be found around a single atom. ... Depiction of a hydrogen atom showing the diameter as about twice the Bohr model radius. ... In atomic physics, the principal quantum number symbolized as n is the first quantum number of an atomic orbital. ... In chemistry, an atomic orbital is the region in which an electron may be found around a single atom. ...


Their wavefunctions take the form of spherical harmonics, and so are described by Legendre polynomials. The various orbitals relating to different values of l are sometimes called sub-shells, and (mainly for historical reasons) are referred to by letters, as follows: In the most restricted usage in quantum mechanics, the wavefunction associated with a particle such as an electron, is a complex-valued square integrable function ψ defined over a portion of space and normalized in such a way that In Max Borns probabilistic interpretation of the wavefunction, the amplitude... Spherical Harmonic is a fantasy novel by Catherine Asaro which tells the story of Pharaoh Dyhianna (Dehya) Selei, ruler of the Skolian Imperialate, after the Radiance War fought by the Imperialate and their enemy Eubian Concord. ... In mathematics, the associated Legendre polynomials, named after Adrien-Marie Legendre, are defined by: These differ from the Legendre polynomials. ...

l Letter Max electrons Shape Name
0 s 2 sphere sharp
1 p 6 two dumbbells principal
2 d 10 four dumbbells diffuse
3 f 14 eight dumbbells fundamental
4 g 18
5 h 22
6 i 26

A mnemonic for the order of the "shells" is some poor dumb fool. Another mnemonic for the order of the "shells" is silly professors dance funny. The letters after the F subshell just follow F in alphabetical order. A sphere is a perfectly symmetrical geometrical object. ... A pair of spinlock dumbbells with 2 kg plates. ...


Each of the different angular momentum states can take 2(2l+1) electrons. This is because the third quantum number ml (which can be thought of loosely as the quantised projection of the angular momentum vector on the z-axis) runs from −l to l in integer units, and so there are 2l+1 possible states. Each distinct nlml orbital can be occupied by two electrons with opposing spins (given by the quantum number ms), giving 2(2l+1) electrons overall. Orbitals with higher l than given in the table are perfectly permissible, but these values cover all atoms so far discovered. Quantization is the procedure of constraining something to a discrete set of values, such as an integer, rather than a continuous set of values, such as a real number. ...


For a given value of the principal quantum number, n, the possible values of l range from 0 to n−1; therefore, the n=1 shell only possesses an s subshell and can only take 2 electrons, the n=2 shell possesses an s and a p subshell and can take 8 electrons overall, the n=3 shell possesses s, p and d subshells and has a maximum of 18 electrons, and so on (generally speaking, the maximum number of electrons in the nth energy level is 2n2). In atomic physics, the principal quantum number symbolized as n is the first quantum number of an atomic orbital. ...


The angular momentum quantum number, l, governs the ellipticity of the probability cloud and the number of planar nodes going through the nucleus. A planar node can be described in an electromagnetic wave as the midpoint between crest and trough which has zero magnitude. A sine wave has a portion with a positive magnitude, a portion with a negative magnitude, and a node, which has zero magnitude. In an s orbital, no nodes go through the nucleus, therefore the corresponding azimuthal quantum number l takes the value of zero. In a p orbital, one node traverses the nucleus and therefore l has the value 1.


Depending on the value of n, the principal quantum number, there is an angular momentum quantum number l and the following series:

n = 1, l = 0, Lyman series (ultraviolet)
n = 2, l = ħ, Balmer series (visible) Wavelength vary from 400 to 700 nm
n = 3, l = 2ħ, Ritz-Paschen series (short wave infrared)
n = 4, l = 3ħ, Pfund series (long wave infrared)

The Lyman series is the series of transitions and resulting emission lines of the hydrogen atom as an electron goes from n ≥ 2 to n = 1 (where n is the principal quantum number referring to the energy level of the electron). ... Two of the balmer lines (α and β) are clearly visible in this emission spectrum of a deuterium lamp. ... The Paschen series is the series of transitions and resulting emission lines of the hydrogen atom as an electron goes from n ≥ 4 to n = 3 (where n refers to the energy level of the electron). ... This article may be too technical for most readers to understand. ...

Addition of quantized angular momenta

For more details on this topic, see Angular momentum coupling.

Given a quantized total angular momentum overrightarrow{j} which is the sum of two individual quantized angular momenta overrightarrow{l_1} and overrightarrow{l_2}, In quantum mechanics, the orbital and spin angular momentum of bodies can interact in angular momentum coupling. ...

overrightarrow{j} = overrightarrow{l_1} + overrightarrow{l_2}

the quantum number j associated with its magnitude can range from | l1l2 | to l1 + l2 in integer steps where l1 and l2 are quantum numbers corresponding to the magnitudes of the individual angular momenta. A quantum number describes the energies of electrons in atoms. ...


Total angular momentum of an electron in the atom

Due to the spin-orbit interaction in the atom, the orbital angular momentum no longer commutes with the Hamiltonian, nor does the spin. These therefore change over time. However the total angular momentum J does commute with the Hamiltonian and so is constant. J is defined through Spin-orbit interaction, in quantum mechanics, is a shift in energy levels due to the potential energy of the spin magnetic moment of the electron in the magnetic field it feels as it moves through the electric field of the nucleus. ... A map or binary operation from a set to a set is said to be commutative if, (A common example in school-math is the + function: , thus the + function is commutative) Otherwise, the operation is noncommutative. ... In physics, Hamiltonian has distinct but closely related meanings. ... The terms spin and SPIN have several meanings, including those primarily discussed as spinning: For spin in sub-atomic physics, see spin (physics) For the stalled aircraft maneuver or any of several forms of loss of control in aircraft, see spin (flight) For the periodical, see Spin Magazine For the... In atomic physics, the total angular quantum momentum numbers parameterize the total angular momentum of a given electron, by combining its orbital angular momentum and its intrinsic angular momentum (i. ... A map or binary operation from a set to a set is said to be commutative if, (A common example in school-math is the + function: , thus the + function is commutative) Otherwise, the operation is noncommutative. ... In physics, Hamiltonian has distinct but closely related meanings. ...

overrightarrow{J} = overrightarrow{L} + overrightarrow{S}

L being the orbital angular momentum and S the spin. The total angular momentum satisfies the same commutation relations as angular momentum, namely This gyroscope remains upright while spinning due to its angular momentum. ...

[J_i, J_j ] = i hbar epsilon_{ijk} J_k

from which follows

left[J_i, J^2 right] = 0

where Ji,j stand for Jx, Jy and Jz.


The quantum numbers describing the system, which are constant over time, are now j and mj, defined through the action of J on the wavefunction ψ A quantum number describes the energies of electrons in atoms. ... This article discusses the concept of a wavefunction as it relates to quantum mechanics. ...

mathbf{J^2boldsymbol{psi}} = hbar^2{j(j+1)}boldsymbol{psi}
mathbf{J_zboldsymbol{psi}} = hbar{m_j}boldsymbol{psi}

So that j is related to the norm of the total angular momentum and mj to its projection along a specified axis.


As with any angular momentum in quantum mechanics, the projection of J along other axes cannot be co-defined with Jz, because they do not commute. This gyroscope remains upright while spinning due to its angular momentum. ... A map or binary operation from a set to a set is said to be commutative if, (A common example in school-math is the + function: , thus the + function is commutative) Otherwise, the operation is noncommutative. ...


Relation between new and old quantum numbers

j and mj, together with the parity of the quantum state, replace the three quantum numbers l, ml and ms (the projection of the spin along the specified axis). The former quantum numbers can be related to the latter. A quantum number describes the energies of electrons in atoms. ... In physics, a parity transformation (also called parity inversion) is the simultaneous flip in the sign of all spatial coordinates: A 3×3 matrix representation of P would have determinant equal to –1, and hence cannot reduce to a rotation. ... A quantum state is any possible state in which a quantum mechanical system can be. ... A quantum number is a number used to parametrise certain properties of particles or other systems in quantum mechanics. ... The terms spin and SPIN have several meanings, including those primarily discussed as spinning: For spin in sub-atomic physics, see spin (physics) For the stalled aircraft maneuver or any of several forms of loss of control in aircraft, see spin (flight) For the periodical, see Spin Magazine For the...


Furthermore, the eigenvectors of j, mj and parity, which are also eigenvectors of the Hamiltonian, are linear combinations of the eigenvectors of l, ml and ms. In linear algebra, the eigenvectors (from the German eigen meaning own) of a linear operator are non-zero vectors which, when operated on by the operator, result in a scalar multiple of themselves. ... In linear algebra, the eigenvectors (from the German eigen meaning own) of a linear operator are non-zero vectors which, when operated on by the operator, result in a scalar multiple of themselves. ... In physics, Hamiltonian has distinct but closely related meanings. ... In linear algebra, the eigenvectors (from the German eigen meaning own) of a linear operator are non-zero vectors which, when operated on by the operator, result in a scalar multiple of themselves. ...


List of angular momentum quantum numbers

In atomic physics, the spin quantum number is a quantum number that parametrizes the intrinsic angular momentum (or spin angular momentum, or simply spin) of a given particle. ... By virtue of its charge and spin motion, an electron develops a magnetic field. ... The total angular quantum momentum numbers parameterize the total angular momentum of a given electron, by combining its orbital angular momentum and its intrinsic angular momentum (i. ...

History

The azimuthal quantum number was carried over from the Bohr model of the atom. The Bohr model was derived from spectroscopic analysis of the atom in combination with the Rutherford atomic model. The lowest quantum level was found to have an angular momentum of zero. To simplify the mathematics, orbits were considered as oscillating charges in one dimension and so described as "pendulum" orbits. In three-dimensions the orbit becomes spherical without any nodes crossing the nucleus, similar to a jump rope that oscillates in one large circle. Azimuth is the horizontal component of a direction (compass direction), measured around the horizon usually from North toward the East, i. ... The Bohr model of the atom The Bohr Model is a physical model that depicts the atom as a small positively charged nucleus with electrons in orbit at different levels, similar in structure to the solar system. ... Extremely high resolution spectrogram of the Sun showing thousands of elemental absorption lines (fraunhofer lines) Spectroscopy is the study of the interaction between radiation (electromagnetic radiation, or light, as well as particle radiation) and matter. ... Ernest Rutherford, 1st Baron Rutherford of Nelson OM PC FRS (30 August 1871 - 19 October 1937), widely referred to as Lord Rutherford, was a nuclear physicist who became known as the father of nuclear physics. ... The term node can refer to: Node, a spatial locus along a standing wave where the wave has minimal amplitude. ...


See also

A quantum number describes the energies of electrons in atoms. ... In atomic physics, the principal quantum number symbolized as n is the first quantum number of an atomic orbital. ... By virtue of its charge and spin motion, an electron develops a magnetic field. ... In atomic physics, the spin quantum number is a quantum number that parametrizes the intrinsic angular momentum (or spin angular momentum, or simply spin) of a given particle. ... The total angular quantum momentum numbers parameterize the total angular momentum of a given electron, by combining its orbital angular momentum and its intrinsic angular momentum (i. ... Quantum mechanics is a physical science dealing with the behaviour of matter and electromagnetic waves on the scale of atoms and subatomic particles. ...

External links


  Results from FactBites:
 
quantum number: Definition and Much More from Answers.com (1149 words)
The principal quantum number (n = 1, 2, 3,...) denotes the eigenvalue of H with the J
However, it should be understood that the elementary particles are quantum states of the standard model of particle physics, and hence the quantum numbers of these particles bear the same relation to the Hamiltonian of this model as the quantum numbers of the Bohr atom does to its Hamiltonian.
Typical quantum numbers related to spacetime symmetries are spin (related to rotational symmetry), the parity, C-parity and T-parity (related to the Poincare symmetry of spacetime).
Azimuthal Quantum Number (862 words)
The angular momentum quantum number, ''l'', governs the ellipticity of the probability cloud and the number of planar nodes going through the nucleus.
The azimuthal quantum number was carried over from the Bohr model of the atom.
The Bohr model was derived as was all of quantum theory from spectroscopic analysis of the atom in combination with the Rutherford atom.
  More results at FactBites »

 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your location
Your comments
Please enter the 5-letter protection code


Lesson Plans | Student Area | Student FAQ | Reviews | Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms.