Infrared and near infrared emission spectra of SbH and SbD Shanshan Yu a , Dejian Fu a , Alireza Shayesteh a , Iouli E. Gordon b , Dominique R.T. Appadoo a , Peter Bernath a,b, * a Department of Chemistry, University of Waterloo, Waterloo, Ont., Canada N2L 3G1 b Department of Physics, University of Waterloo, Waterloo, Ont., Canada N2L 3G1 Received 13 July 2004; in revised form 13 September 2004 Abstract The X 3 R  ground state vibration–rotation spectrum of SbH and the near infrared spectra of the b 1 R + –X 3 R  transitions of SbH and SbD have been measured at high resolution by Fourier transform spectroscopy. The SbH and SbD radicals were generated in a tube furnace with a D.C. discharge of a flowing mixture of argon, hydrogen (or deuterium), and antimony vapor. In the infrared region, the 1–0 and 2–1 bands of the three components (0 + ,1 e , and 1 f ) as well as the 0 + component of the 3–2 band were observed for 121 SbH and 123 SbH. In the near infrared region, the 0–0, 1–1, and 2–2 bands of the b 1 R + –X 3 R  system of both SbH and SbD as well as the 3–3 band of SbD were observed. Except for a few lines, the antimony isotopic shift was not resolved for these electronic spectra. The present data set was combined with the available ground state data on SbD and a 1 D data for SbH and SbD from pre- vious work, and a least-squares fit was performed for each of the four isotopologues: 121 SbH, 123 SbH, 121 SbD, and 123 SbD. Improved spectroscopic constants were obtained for the observed vibrational levels of the X 3 R  , a 1 D, and b 1 R + states of these four isotopologues. In addition, all the above data were also fitted simultaneously to a multi-isotopologue Dunham model, which yielded Dunham constants and Born–Oppenheimer breakdown parameters for these three electronic states. Interestingly, we found that Born–Oppenheimer breakdown corrections were also required for some of the spin–spin and spin–rotation parameters of the X 3 R  state. Ó 2004 Elsevier Inc. All rights reserved. Keywords: SbH; SbD; Infrared spectra; Electronic spectra; Spin–spin; Spin–rotation; Born–Oppenheimer; Dunham 1. Introduction SbH and SbD radicals are the least studied of the Group V diatomic hydrides. The first observation of SbH and SbD was reported in 1972 by Bollmark and Lindgren [1], and Basco and Yee [2], who independently measured the A 3 P i –X 3 R  absorption spectra by flash photolysis of stibine. Seven years later, Bollmark and Lindgren [3] made new observations of the A 3 P i –X 3 R  transition, which permitted them to perform a detailed rotational analysis and derive molecular constants for the A 3 P i and X 3 R  states. In 1981, Bollmark et al. [4] studied the absorption spectra of the SbH and SbD in the region 1900–1580 A ˚ by the flash discharge technique and some improvements of the ground state constants were obtained together with information about several new upper states. More precise molecular constants for the X 3 R  ground state of SbH were obtained by Stackmann et al. [5], who studied the spectrum of SbH by the infrared laser magnetic resonance technique. Im- proved spectroscopic constants for the X 3 R  ground state of SbD were obtained by Urban et al. [6] in their study of the fundamental bands and the 2–1 hot bands of SbH and SbD with a tunable diode la- ser. Recently, Beutel et al. [7] measured the 0–0 and 0022-2852/$ - see front matter Ó 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.jms.2004.09.012 * Corresponding author. Fax: +1 519 746 0435. E-mail address: bernath@uwaterloo.ca (P. Bernath). www.elsevier.com/locate/jms Journal of Molecular Spectroscopy 229 (2005) 257–265