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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