title: Orientation of benzene in supersonic expansions, probed by IR-laser absorption and by molecular beam scattering.
abstract: This work represents the first experimental demonstration that planar molecules tend to travel as a "frisbee" when a gaseous mixture with lighter carriers expands into a vacuum, the orientation being due to collisions. The molecule is benzene, the prototype of aromatic chemistry. The demonstration is via two complementary experiments: interrogating benzene by IR-laser light and controlling its orientation by selective scattering on rare gas targets. The results cast new light on the microscopic mechanisms of collisional alignment and suggest a useful way to produce intense beams of aligned molecules, permitting studies of steric effects in gas-phase processes and in surface catalysis.
authors.affiliation: Dipartimento di Chimica and Dipartimento di Ingegneria Civile ed Ambientale, Università di Perugia, 060123-Perugia, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Pirani
authors.forename: D
authors.initials: D
authors.lastname: Cappelletti
authors.forename: M
authors.initials: M
authors.lastname: Bartolomei
authors.forename: V
authors.initials: V
authors.lastname: Aquilanti
authors.forename: M
authors.initials: M
authors.lastname: Scotoni
authors.forename: M
authors.initials: M
authors.lastname: Vescovi
authors.forename: D
authors.initials: D
authors.lastname: Ascenzi
authors.forename: D
authors.initials: D
authors.lastname: Bassi