Melville, Todd C.2014-10-2120022002AAINQ67654http://hdl.handle.net/10222/55828High-resolution laser induced fluorescence and resolved fluorescence have been utilized to examine the A2pi - X2Sigma+ electronic transition of gaseous 174Yb35Cl and 172Yb 35Cl. In total, more than 2600 line positions have been employed in least-squares fits of molecular parameters. The A 2pi and B2Sigma+ states are shown to act as a unique perturber pair. The interaction between the A2pi and X2 Sigma+ states has been investigated, and is shown to be the primary contributor to the spin-rotation splitting in the ground state.In the first observation of YbS, the A0+ - X0+ and B0+ - X0+ transitions have been investigated at both low- and high-resolution using laser absorption spectroscopy. The A0+ state experiences both vibrational and rotational perturbations. A partial deperturbation analysis has provided deperturbed parameters for both the A0+ state and the perturbing state. The B0+ state is subject to a strong predissociation in the upsilon = 0 vibrational level. Molecular parameters for all of the observed levels are reported.The A2pi - X˜ 2Sigma+ transition in YbOH has been examined in the first reliable spectroscopic observation of a lanthanide monohydroxide. A vibrational analysis of this system has provided estimates for the vibrational frequencies of the Yb-O stretching and Yb-O-H bending modes. A rotational analysis of the (000) - (000) band indicates the molecule has a linear geometry in both electronic states. The unusual behaviour of the ground state spin-rotation parameter is discussed and compared to that of the isoelectronic YbF molecule.Numerous bands in the CaS A1Sigma + - X1Sigma+ transition have been investigated using high-resolution laser spectroscopy. The A1Sigma+ state is extensively perturbed by at least three other electronic states (which may include spin-components of a triplet state). A deperturbation analysis of the nine observed level crossings has provided estimates of molecular parameters for the A1Sigma+ and perturbing states. The identity of the perturbers, though not established unequivocally, is discussed in terms of the low-lying a3pi and A'1pi states.Thesis (Ph.D.)--Dalhousie University (Canada), 2002.Chemistry, Analytical.Chemistry, Physical.text