title: Toward an improved understanding of the AsH2 free radical: laser spectroscopy, ab initio calculations, and normal coordinate analysis.
abstract: Spectra of the Ã(2)A(1)-X̃(2)B(1) transition of the jet-cooled AsD(2) and AsHD isotopologues of the arsino radical have been studied by laser induced fluorescence and wavelength resolved emission techniques. A high-resolution spectrum of the AsD(2) 0(0)(0) band has been recorded, and an improved r(0) structure [r(0)(') = 1.487(4) Å, θ(0)(') = 123.0(2)°] for the Ã state has been determined from the rotational constants. To aid in the analysis of the vibrational levels, an ab initio potential energy surface of the X̃(2)B(1) state has been constructed and the rovibronic energy levels of states on that potential have been determined using a variational method. The vibrational levels observed in wavelength resolved emission spectra have been fitted to a local mode Hamiltonian with most anharmonic parameters fixed at ab initio values, and the resulting harmonic frequencies have been used to perform a normal coordinate analysis which yielded an improved set of quadratic force constants and an estimate of the equilibrium ground state structure.
authors.affiliation: Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-055, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Grimminger
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: Clouthier