title: Nitrous oxide tetramer has two highly symmetric isomers.
abstract: Infrared spectra of the nitrous oxide tetramer, (N(2)O)(4), are studied in the region of the N(2)O ν(1) fundamental band (∼2200 cm(-1)). The spectra are observed using a tunable diode laser to probe a pulsed supersonic jet expansion. Parallel (ΔK = 0) bands are observed for the previously observed isomer of (N(2)O)(4), which is confirmed by isotopic substitution to have an oblate symmetric rotor structure with D(2d) symmetry. A distinct new isomer of (N(2)O)(4) is observed by means of a perpendicular (ΔK = ±1) band. It has a prolate symmetric rotor structure with S(4) symmetry. These isomers represent two distinct, but almost equally favorable, ways of bringing together a pair of nonpolar N(2)O dimers to form a tetramer. It is not clear at present which one represents the true ground state.
authors.affiliation: Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada.
authors.forename: J Norooz
authors.initials: JN
authors.lastname: Oliaee
authors.forename: M
authors.initials: M
authors.lastname: Dehghany
authors.forename: N
authors.initials: N
authors.lastname: Moazzen-Ahmadi
authors.forename: A R W
authors.initials: AR
authors.lastname: McKellar