The photoelectron spectrum of 7b-methyl-7bH-cyclopent[cd]indene

Abstract

The He¹ photoelectron (p.e.) spectrum of 7b-methyl-7bH-cyclopent[cd]indene (1) has been recorded. The first four bands are assigned to ionization events from π-orbitals related to the perimeter of [10]annulene. This assignment is based on model calculations using the HMO and the MIND0/3 model. The p.e. spectrum of (1) is compared with that of 1,6-methano[10]annulene (3). The rearrangement of (1) to its 2aH isomer (4) is also discussed.