1978/03/08 by Thomas Bally, Edwin Haselbach · 3 citations
Physics and Astronomy · Chemistry · #Advanced Chemical Physics Studies #Molecular Spectroscopy and Structure #Organic Chemistry Cycloaddition Reactions
paper · doi:10.1002/hlca.19780610223
openalex publication_date 1978/03/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/05/21
Abstract The photoelectron spectrum of tris (methylidene)‐cyclopropane 1 (“[3]radialene”) is reported and the electronic states of 1 + assigned. Jahn‐teller activity in the degenerate states of 1 + is discussed. Differences in the Franck‐Condon profile of the first PE band and the Rydberg series in the Vacuum‐UV./UV. absorption spectrum indicate for the Rydberg series (n=3) a 1 A″ 2 ‐species, which supports earlier tentative proposals. The high intensity absorption in the 5.5 eV‐6 eV energy range of the latter spectrum recorded earlier are definitely due to impurities. The vibrational fine structure of a weak band system around 5.5 eV in our spectrum suggests for this transition S 0 →S 2 ( 1 A′ 1 ), which is dipole forbidden but borrows intensity from S 1 ( 1 E′) trough vibronic coupling via an e′‐mode. From vapor pressure measurements ε(λ max =289 nm) = 9390± 1170 for gaseous 1 was found.