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	Molecular orbital - Wikipedia, the free encyclopedia
		The linear combination of atomic orbitals approximation for molecular orbitals was introduced in 1929 by Sir John Lennard-Jones.
		Molecular structure relies on the outermost (valence) electrons of the atoms, which are usually of comparable energy.
		To obtain quantitative values for the molecular energy levels, one needs to have molecular orbitals which are such that the configuration interaction (CI) expansion converges fast towards the full CI limit.
	en.wikipedia.org /wiki/Molecular_orbital (865 words)

	Encyclopedia: Molecular orbital
		The s orbitals are lower in energy than the p orbitals, and the orbitals on oxygen are slightly lower in energy than the corresponding orbitals on carbon (oxygen is more electronegative).
		The molecular orbitals (MO) of carbon monoxide are formed by "mixing" of atomic orbitals (forming linear combinations of them, or in simplistic terms adding them to each other or subtracting them from each other).
		Indeed the lobes of (bonding) molecular orbitals are larger on the oxygen atom.
	www.nationmaster.com /encyclopedia/Molecular-orbital (2177 words)

	Kids.net.au - Encyclopedia Molecular orbital - (Site not responding. Last check: 2007-10-21)
		Molecular symmetries map stationary states to stationary states, so any collection of degenerate molecular orbitals must transform according to some representation[?] of the symmetry group.
		This actually happens whether the atoms have an energy advantage to grouping or not—strictly speaking, there is mixing between orbitals of atoms light-years away from each other, and although the resulting orbitals do not have energy different from those of the atomic orbitals, the electron density is always high near all the nuclei.
		To make up for this, we often take linear combinations of molecular orbitals so that electron density is localized around atoms, and between them (hybridized bonds), but it should be remembered that these are not stationary states, so although they are useful in treating electron density they have no real meaning in terms of energy.
	www.kidsseek.com /encyclopedia-wiki/mo/Molecular_orbital (791 words)

	Molecular Orbital Theory
		Molecular orbital theory is more powerful than valence-bond theory because the orbitals reflect the geometry of the molecule to which they are applied.
		Molecular orbitals are obtained by combining the atomic orbitals on the atoms in the molecule.
		To sort out the relative energies of the six molecular orbitals formed when the 2p atomic orbitals on a pair of atoms are combined, we need to understand the relationship between the strength of the interaction between a pair of orbitals and the relative energies of the molecular orbitals they form.
	chemed.chem.purdue.edu /genchem/topicreview/bp/ch8/mo.html (1304 words)

	Molecular Orbital Theory
		The goal of molecular orbital theory is to describe molecules in a similar way to how we describe atoms, that is, in terms of orbitals, orbital diagrams, and electron configurations.
		Molecular orbitals are formed from the overlap of atomic orbitals.
		Because electrons in the molecular orbital are lower potential energy than in separate atomic orbitals, energy would be required to shift the electrons back into the 1s orbitals of separate atoms.
	www.mpcfaculty.net /mark_bishop/molecular_orbital_theory.htm (1632 words)

	Molecular Orbital Diagrams (Site not responding. Last check: 2007-10-21)
		The interactions of the atomic orbitals to form molecular orbitals is represented by an energy diagram called a molecular orbital diagram.
		The dotted lines are used to connect molecular orbitals with the atomic orbitals that "mixed" to form the molecular orbital.
		The lower energy orbital is the bonding orbital; the higher energy orbital is the anti-bonding orbital.
	www.chm.davidson.edu /ChemistryApplets/MolecularOrbitals/MO.html (507 words)

	SparkNotes: Organic Molecular Orbitals: Molecular Orbital Theory
		Molecular orbital theory holds, as its name suggests, that electrons reside in molecular orbitals that are distributed over the entire molecule.
		Antibonding orbitals are denoted with an asterisk (*).
		The bonding molecular orbital is "bonding" in the sense that it is lower in energy than its component atomic orbitals.
	www.sparknotes.com /chemistry/organic1/orbitals/section2.rhtml (888 words)

	Organic Chemistry at Penn State: Quantum Primer III (Site not responding. Last check: 2007-10-21)
		Molecular orbitals (MO) are made of atomic orbitals.
		All atoms in the molecule provide their atomic orbitals for construction of MO, but not all atomic orbitals must participate in all MO. The number of MO is equal to the number of atomic orbitals used to generate them.
		We have to use each atomic orbital completely, we have to generate normalized molecular orbitals (MOs), and the number of MOs must be equal to the number of atomic orbitals that we have started with.
	courses.chem.psu.edu /chem38/quantum/quantum3.html (1337 words)

	Chemistry 101A, Atomic and Molecular Oribtals Page
		The orbitals are not all shown on the same scale (except for the 1s and 2s orbitals, which are on the same scale).
		Molecular orbitals, as the name implies, are orbitals representing the motion of electrons in molecules.
		The 2p-sigma orbital is a bonding orbital which can be approximated by two 2p orbitals with their electron density lobes pointing toward each other.
	www.chem.arizona.edu /~salzmanr/orbitals.html (1640 words)

	Molecular Orbitals - Introduction
		For example, the 2s orbital in the lithium atom is a function which determines the motion of an electron in the potential field of the nucleus and in the average field of the two electrons in the 1s orbital.
		Once the forms and properties of the molecular orbitals are known, the electronic configuration and properties of the molecule are again determined by assigning electrons to the molecular orbitals in the order of increasing energy and in accordance with the Pauli exclusion principle.
		In molecular orbital theory the bond is described in terms of a single orbital which is determined by the field of both nuclei.
	www.chemistry.mcmaster.ca /esam/Chapter_8/intro.html (541 words)

	Details
		When constructing the molecular orbitals it is common practice to use the valence orbitals to form the molecular orbitals.
		This results in an anti-bonding molecular orbital that is high in energy and tends to tear apart the molecule.
		In a bonding molecular orbital, the probability of finding the electrons on one, both or between the atoms is quite high.
	www.chembio.uoguelph.ca /educmat/chm729/band/detail.htm (711 words)

	Introduction to Molecular Orbital Theory
		The upper molecular orbital has a node in the electronic wave function and the electron density is low between the two positively charged nuclei.
		The energy of the upper orbital is greater than that of the 1s atomic orbital, and such an orbital is called an antibonding molecular orbital.
		This highest occupied orbital has a lobe pointing away from the three hydrogens, and corresponds to a lone pair orbital localized upon the nitrogen, whereas the three lowest energy MO's lead to the description of the three N-H bonds of the Lewis structure.
	www.ch.ic.ac.uk /vchemlib/course/mo_theory/main.html (2412 words)

	Molecular orbitals
		These orbitals are not occupied in the ground states of the parent atoms, so we need not concern ourselves with them, although in a more thorough treatment their existence would need to be taken into account.
		Although two atomic p orbitals will be expected to split into bonding and antibonding orbitals just as before, it turns out that the extent of this splitting, and thus the relative energies of the resulting molecular orbitals, depend very much on the nature of the particular p orbital that is involved.
		In many ways the resulting molecular orbitals are similar to what we got when s atomic orbitals combined; the bonding orbital has a large electron density in the region between the two nuclei, and thus corresponds to the lower potential energy.
	www.chem1.com /acad/webtext/chembond/cb08.html (3496 words)

	Molecular Orbital Bonding (Site not responding. Last check: 2007-10-21)
		However, since no more than two electrons can be in any orbital, whether it be an atomic orbital or a molecular orbital, the other two electrons must be in a higher energy molecular orbital.
		Molecular orbital theory tells us that when atoms come together their atomic orbitals overlap.
		The number of molecular orbitals is always the same as the number of atomic orbitals they came from.
	people.depauw.edu /jhansen/Chem120S04/MObonding.html (380 words)

	SparkNotes: Molecular Orbitals: Molecular Orbital Theory
		Molecular orbital theory posits the notion that electrons in molecules likewise exist in different orbitals that give the probability of finding the electron at particular points around the molecule.
		Notice that the orbitals of the separated atoms are written on either side of the diagram as horizontal lines at heights denoting their relative energies.
		From the orbital correlation diagram above you should notice that the amount of stabilization due to bonding is equal to the amount of destabilization due to antibonding, because there are two electrons in the bonding orbital and two electrons in the antibonding orbital.
	www.sparknotes.com /chemistry/bonding/molecularorbital/section1.html (1810 words)

	Molecular Orbital Theory (Site not responding. Last check: 2007-10-21)
		The structure and use of a molecular orbital diagram is explained.
		Comparison of the atomic and molecular orbitals permits determination of the which atomic orbitals interacted to form the molecular orbital.
		Molecular Orbital Diagram: Carbon Dioxide (CO The molecular orbital diagram for hydrogen fluoride is displayed.
	www.chm.davidson.edu /ChemistryApplets/MolecularOrbitals (343 words)

	Molecular Orbital (Site not responding. Last check: 2007-10-21)
		These electrons are arranged in three orbitals, the innermost orbital having two electrons, and...
		The study further predicts that the g-orbital electrons are involved in forming molecular orbitals, a bonding configuration that may impart distinct chemical...
		These basis are synonimous with the atomic orbitals for the atoms in the molecules.
	www.wikiverse.org /molecular-orbital (941 words)

	Duran: Chapter Twelve Molecular Orbital Theory (Site not responding. Last check: 2007-10-21)
		The Molecular Orbital Theory does a good job of predicting elctronic spectra and paramagnetism, when VSEPR and the V-B Theories don't.
		One of the molecular orbitals is lower in energy.
		Below is a molecular orbital energy diagram for the hydrogen molecule.
	www.chem.ufl.edu /~chm2040/Notes/Chapter_12/theory.html (706 words)

	Grandinetti (Site not responding. Last check: 2007-10-21)
		In Molecular Orbital Theory we view the bonding of the two H-atoms as partial constructive interference between standing wavefunctions of the 1s orbitals.
		When atomic orbitals are combined to give molecular orbitals, the number of molecular orbitals formed equals the number of atomic orbitals used.
		A molecular orbital (like an atomic orbital) can contain no more than two electrons (Pauli Exclusion Principle), and are filled starting with the lowest energy orbital first.
	www.chemistry.ohio-state.edu /~grandinetti/teaching/Chem121/lectures/MOTheory/MOTheory.html (526 words)

	Re: Whats up with the Lewis dot structure of sulfate?
		Overlap of the remaining one-electron orbitals results in a double bond, with one lone pair of electrons on carbon and two on oxygen; all this is shown schematically in Figure 4.
		orbitals, and combine with appropriate combinations of the p atomic orbitals on oxygen (that is, the p orbitals which point toward sulfur).
		Molecular orbital theory bears out the simple Lewis picture shown above in Figure 13; this is also the conclusion of A. Reed and P.v.R. Schleyer, Journal of the American Chemical Society 109, 7362-73 (1987), ibid.
	www.madsci.org /posts/archives/jan2000/949098457.Ch.r.html (1495 words)

	Atomic & Molecular Orbitals
		The electron densities along the x, y and z axes of the 2p orbitals are clearly shown in the figure; the nodes are the points at the origin and at these points, there is zero probability of finding the electron.
		As the two 1s atomic orbitals approach each other and begin to overlap, there is a decrease in the net energy of the system because the electrons in each atom tend to become attracted to the positive nucleus of the other atom, as well as its own nucleus.
		In molecular orbital theory, the number of atomic orbitals used to make the covalent bond must equal the total number of molecular orbitals in the molecule.
	www.chem.uic.edu /web1/ocol/SB/1-2.htm (501 words)

	The Properties of Reactant Molecules
		The most common is a two layer model, the outer layer treated using molecular mechanics (or even a simpler unified field model), the inner one treated using MO theories.
		The bonding in these molecules is not yet known, and therefore a molecular mechanics approach, which requires explicit partitioning of the electrons and assignment of atom types, is not perhaps the best starting point.
		Molecular orbital methods can help identify the origin of the aromaticity (from the nature of the MOs themselves) and the quantitative value of the aromaticity using an computed index known as NICS.
	www.ch.ic.ac.uk /local/organic/mod/mo_4.html (1930 words)

	SHMO- The Simple Huckel Molecular Orbital Theory Calculator (Site not responding. Last check: 2007-10-21)
		The theoretical basis for the method is described in Orbital Interaction Theory of Organic Chemistry, by A.
		Besides performing conventional SHMO calculations, SHMO permits easy changes of orbital electronegativities (the Huckel coulomb integrals, alpha) and intrinsic orbital interaction values (the Huckel resonance integrals, beta) to illustrate the effects of interacting orbital energies orbital energy differences and overlaps on the resultant molecular orbital energies and polarizations.
		Orbital selection is by clicking on the orbital energy display or step up/step down buttons.
	www.chem.ucalgary.ca /SHMO/index.html (285 words)

	Molecular Torch: Orbital Kondo effect in carbon nanotubes (Site not responding. Last check: 2007-10-21)
		Orbital Kondo effect in carbon nanotubes: "Progress in the fabrication of nanometre-scale electronic devices is opening new opportunities to uncover deeper aspects of the Kondo effect�a characteristic phenomenon in the physics of strongly correlated electrons.
		We use a magnetic field to tune spin-polarized states into orbital degeneracy and conclude that the orbital quantum number is conserved during tunnelling.
		When orbital and spin degeneracies are present simultaneously, we observe a strongly enhanced Kondo effect, with a multiple splitting of the Kondo resonance at finite field and predicted to obey a so-called SU(4) symmetry."
	www.moleculartorch.com /2005/03/orbital-kondo-effect-in-carbon.html (297 words)

	molecular orbital II
		However, the actual molecular orbitals are somewhat different (and become more different as the two elements in the heteronuclear molecule differ more in orbital energy).
		Remember that the square of the coefficient of a particular AO in a given MO is the percentage of the MO derived from that AO.
		Thus we say that this orbital is predominately O s orbital in character (and is predominately a lone pair of electrons located on the oxygen atom).
	www.wellesley.edu /Chemistry/chem120/mo2.html (269 words)

	molecular orbital I (Site not responding. Last check: 2007-10-21)
		In the molecular orbital model, orbitals on individual atoms interact to produce new orbitals, called molecular orbitals, which are now identified with the whole molecule.
		In the case of diatomic molecules, the interactions are easy to see and may be thought of as arising from the constructive interference of the electron waves (orbitals) on two different atoms, producing a bonding molecular orbital, and the destructive interference of the electron waves, producing an antibonding molecular orbital
		The movies show bonding and antibonding molecular orbital formation from both a contour diagram and a surface perspective.
	www.wellesley.edu /Chemistry/chem120/mo1.html (250 words)

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