title: An experimental and theoretical study of the electronic spectrum of the HBCl free radical.
abstract: Following our previous discovery of the spectra of the HBX (X = F, Cl, and Br) free radicals [S.-G. He, F. X. Sunahori, and D. J. Clouthier, J. Am. Chem. Soc. 127, 10814 (2005)], the Ã(2)A(″)Π-X̃(2)A(') band systems of the HBCl and DBCl free radicals have been studied in detail. The radicals have been prepared in a pulsed electric discharge jet using a precursor mixture of BCl3 and H2 or D2 in high pressure argon. Laser-induced fluorescence (LIF) and single vibronic level emission spectra have been recorded to map out the ground and excited state vibrational energy levels. The band system involves a linear-bent transition between the two Renner-Teller components of what would be a (2)Π electronic state at linearity. We have used high level ab initio theory to calculate the ground and excited state potential energy surfaces and have determined the vibronic energy levels variationally. The theory results were used to assign the LIF spectra which involve transitions from the ground state zero-point level to high vibrational levels of the excited state. The correspondence between theory and experiment, including the transition frequencies, upper state band symmetries, and H, B, and Cl isotope shifts, was used to validate the assignments.
authors.affiliation: Department of Chemistry, The University of Jordan, Amman 11942, Jordan.
authors.forename: Mohammed A
authors.initials: MA
authors.lastname: Gharaibeh
authors.affiliation: Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA.
authors.forename: Ramya
authors.initials: R
authors.lastname: Nagarajan
authors.affiliation: Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA.
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: Clouthier
authors.affiliation: Dipartimento di Chimica Industriale "Toso Montanari," Università di Bologna, Viale Risorgimento 4, 40136 Bologna, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Tarroni