Q107 · CSIR NET Chemistry, December 2013
Paper: CSIR NET December 2013 · Subject: Physical Chemistry · Chapter: Quantum Chemistry · Topic: Huckel MO Theory · Marks: 2 · Difficulty: Easy
The energy for a single electron excitation in cyclopropenium cation in Huckel theory is
(a)$\beta$
(b)$2 \beta$
(c)$3 \beta$
(d)$4 \beta$
Answer
Answer: C ✓ checked by 4AB · confidence high
The source book printed no answer; this one was worked out and checked — see the explanation.
Explanation
Cyclopropenium cation: two electrons in α + 2β, empty degenerate pair at α − β. Excitation energy = (α − β) − (α + 2β) = −3β, i.e. 3|β|.
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