Why do molecules show broad bands where atoms show sharp lines?

• Molecules are always hotter than atoms
• Each jump bundles many sub jumps
• Molecules contain no electrons

What does the Franck-Condon principle say about an electronic jump?

• Nuclei stand still, so it is vertical
• The nuclei move first, then the electron follows
• Electrons and nuclei always move together

Longer conjugation moves absorption toward longer wavelength.

What sets the brightest peak inside an electronic band?

• The temperature of the lamp
• The number of molecules in the room
• The vibrational overlap

Two dyes differ by one double bond. Which absorbs at longer wavelength, and why?

• The shorter one, because small gaps cost more
• More conjugated, so gap is narrower
• Both absorb identically whatever the structure

A carbonyl compound shows a strong deep ultraviolet band and a weak one nearer the visible. How do you assign them?

• Strong is n to pi*, weak is pi to pi*
• Strong is pi to pi*, weak is n to pi*
• Both bands are the same transition

A metal complex changes from a weak field ligand to a strong field one. What happens to its colour?

• Absorption moves blue as split widens
• Absorption shifts toward the red as the split widens
• The colour cannot change whatever the ligand

A student draws the electronic jump as a diagonal arrow with nuclei shifting mid leap. What is wrong?

• Nothing, diagonal arrows are standard
• Arrows are never drawn between curves
• Vertical, since nuclei stand still