Difference between revisions of "Electronic Coupling Between Orbitals"

From CleanEnergyWIKI
Jump to navigation Jump to search
Line 10: Line 10:


In the Hückel approximation this energy is the same for all carbon p-orbitals that are adjacent to on another and is called Β.
In the Hückel approximation this energy is the same for all carbon p-orbitals that are adjacent to on another and is called Β.
 
<br clear='all'>
[[Image:Beta-nonadjacent.png|thumb|200px|Non- Adjacent p orbitals do not interact]]
[[Image:Beta-nonadjacent.png|thumb|200px|Non- Adjacent p orbitals do not interact]]
For atoms that are not adjacent to one another &Beta; is taken to be zero.  Thus in the Hückel approximation there is no interaction between nonadjacent atoms.
[[Image:Beta-energydiagram.png|thumb|300px|]]
Through this coupling of atomic orbitals, molecular orbitals can formed by a constructive and destructive combination of the atomic orbitals.

Revision as of 12:47, 19 May 2009

Return to Molecular Orbitals Menu | Next Topic

Error creating thumbnail: Unable to save thumbnail to destination
Adjacent p orbitals can interact

We will discuss the electronic structure of π-conjugated organic molecules at various levels of complexity. π-conjugated molecules have a sigma electron framework and π electron framework.

Here we start at the simplest level that is basically derived from a Hückel Molecular Orbital approach in order to understand conjugated systems.

In this model, orbitals that are on atoms that are directly σ-bonded to one another and whose p-orbitals are in a plane can interact. This interaction is called the "electronic coupling" between the orbitals and has units of energy.

In the Hückel approximation this energy is the same for all carbon p-orbitals that are adjacent to on another and is called Β.

Non- Adjacent p orbitals do not interact

For atoms that are not adjacent to one another Β is taken to be zero. Thus in the Hückel approximation there is no interaction between nonadjacent atoms.

Beta-energydiagram.png

Through this coupling of atomic orbitals, molecular orbitals can formed by a constructive and destructive combination of the atomic orbitals.