Abstract
The origin of the positive A term in the magnetic circular dichroism spectrum of the A 0 0 band of the 1 B 2u ← 1 A 1g transition of benzene in the vapour phase is investigated. The appearance of this A term is shown to be consistent with the vibronic borrowing of angular momentum from the allowed 1 E 1u ← 1 A 1g transition for which a positive A term has also been observed. Comparison is made with a calculation of the A term in the 1 B 1u ← 1 A 1g transition of benzene.