How Does the Conjugated System of Chlorophyll Affect Photon Absorption?

[obiwankenobi]

Homework Statement

Why does the conjugated system (alternance of single and double bonds) of chlorophylles help with photon absorption?

The Attempt at a Solution

Since two carbon atoms are equal in electric negativity, no one atom hogs the electrons. In this way, it is easier for photons to excite the electrons. However, I don't understand why single or double bonds would make a difference.

Thanks! [/B]

 

[Bystander]

Think in terms of the "length" of the conjugated system.

 

[obiwankenobi]

Double bonds make the molecule shorter than single bonds? How does that help with photon absorption?

 

[Bystander]

Of the SYSTEM of bonds (plural).

 

[obiwankenobi]

Thanks! But how does that relate to photon absorption?

 

[Ygggdrasil]

Have you studied the particle in a box? How does the spacing of the energy states change when the length of the box changes?