title: Cavity ring-down spectroscopy of the torsional motions of 1,4-bis(phenylethynyl)benzene.
abstract: The torsional motions of jet-cooled 1,4-bis(phenylethynyl)benzene (BPEB), a prototype molecular wire, were studied using cavity ring-down spectroscopy in the first UV absorption band (316-321 nm). The torsional spectrum of 1,4-bis(phenylethynyl)-2,3,5,6-tetradeuteriobenzene was also recorded in the gas phase. Both spectra were successfully simulated using simple cosine potentials to describe the torsional motions. The ground-state barrier to rotation was estimated to be 220-235 cm(-1), which is similar to that of diphenylacetylene (tolane). Complementary DFT calculations were found to overestimate the torsional barrier.
authors.affiliation: University of Durham, Department of Chemistry, South Road, Durham DH1 3LE, UK.
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Greaves
authors.forename: Emma L
authors.initials: EL
authors.lastname: Flynn
authors.forename: Emma L
authors.initials: EL
authors.lastname: Futcher
authors.forename: Eckart
authors.initials: E
authors.lastname: Wrede
authors.forename: Donocadh P
authors.initials: DP
authors.lastname: Lydon
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Low
authors.forename: Simon R
authors.initials: SR
authors.lastname: Rutter
authors.forename: Andrew
authors.initials: A
authors.lastname: Beeby