title: High-resolution spectroscopy and structure of osmium tetroxide. A benchmark study on 192OsO4.
abstract: Osmium tetroxide (OsO(4)) is a heavy tetrahedral molecule that constitutes a benchmark for quantum chemistry calculations. Its favorable spin statistics (due to the zero nuclear spin of oxygen atoms) is such that only A(1) and A(2) (T(d) symmetry) rovibrational levels are allowed, leading to a dense but quite easily resolvable spectrum. We reinvestigate here the ν(1)/ν(3) stretching fundamental (940-980 cm(-1)) dyad region and perform new assignments and effective Hamiltonian parameter fits for the main isotopologue ((192)OsO(4)). We also investigate the ν(2)/ν(4) bending fundamental dyad (300-360 cm(-1)) for the first time and perform a preliminary analysis. New experimental data have been obtained at 0.001 cm(-1) resolution using an isotopically pure (192)OsO(4) sample and the Synchrotron SOLEIL light source. Assignments and analyses were performed using SPVIEW and XTDS software, respectively. We provide precise effective Hamiltonian parameters, including the band centers for all of the fundamental levels and rotational constants for the ground state and for all four fundamental levels. We discuss isotopic shifts, estimate the equilibrium rotational constant B(e), and derive a precise value for the equilibrium bond length r(e)(Os-O) = 1.70919(16) Å. We also performed experiments to measure for the first time the IR integrated intensities for the ν(2)/ν(4) bending fundamental dyad. These new data are compared to current ab initio predictions.
authors.affiliation: Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), CNRS UMR 6303, Université de Bourgogne, 9 Avenue Alain Savary, BP 47870, F-21078 Dijon Cedex, France. Maud_Louviot@etu.u-bourgogne.fr
authors.forename: Maud
authors.initials: M
authors.lastname: Louviot
authors.forename: Vincent
authors.initials: V
authors.lastname: Boudon
authors.forename: Laurent
authors.initials: L
authors.lastname: Manceron
authors.forename: Pascale
authors.initials: P
authors.lastname: Roy
authors.forename: Dionisio
authors.initials: D
authors.lastname: Bermejo
authors.forename: Raúl Z
authors.initials: RZ
authors.lastname: Martínez