In the following models, sp² carbon atoms are dark gray and the R-substituents on the double bond are light gray. The p-orbitals in the original display are spheres above and below the plane of the sigma bonds. The different phases of the p and π-orbitals are colored blue and red. Regions in which adjacent orbitals undergo a phase change are called nodes. Orbital electron density is zero in such regions. A brief delay will occur when a new display is selected.
The models can be rotated by clicking on the structure and dragging the mouse. Holding the shift key during this operation allows zooming.

In the following models, the sp² carbon atoms of the diene are dark gray and the R-substituents on the double bonds are light gray. The contributing p-orbitals in the display are spheres above and below the plane of the sigma bonds. The different phases of these orbitals are colored blue and red, and are separated by nodal surfaces at which electron density is zero. The four π-orbitals are formed by overlap of p-orbitals having like phases. The lowest energy π-orbital, π₁, has a single nodal plane, that of the carbon atoms of the diene. The p-orbital components of higher energy π-orbitals may be viewed by clicking appropriate buttons under the display. An increasing number of nodes parallels the increase in energy. The two lowest energy π-orbitals are bonding. The two higher energy orbitals, π₃* and π₄* are antibonding. The HOMO is π₂; the LUMO is π₃*.
The models can be rotated by clicking on the structure and dragging the mouse. Holding the shift key during this operation allows zooming.

In the following models, the sp² carbon atoms of the diene are dark gray and the R-substituents on the double bonds are light gray. The p-orbitals in the display are spheres above and below the plane of the sigma bonds. The different phases of these orbitals are colored blue and red, and are separated by nodal surfaces at which electron density is zero. The four π-orbitals are formed by overlap of p-orbitals having like phases. The lowest energy π-orbital, π₁, has a single nodal plane, that of the atoms of the diene. The π-orbital coefficients at C-2 and C-3 are greater than the coefficients at the terminal carbons. The orbital components of higher energy π-orbitals may be viewed by clicking appropriate buttons under the display. An increasing number of nodes parallels the increase in energy, and the orbital coefficients at the four diene carbons also change. The two lowest energy π-orbitals are bonding. The two higher energy orbitals, π₃* and π₄* are antibonding. The HOMO is π₂; the LUMO is π₃*.
The models can be rotated by clicking on the structure and dragging the mouse. Holding the shift key during this operation allows zooming.