UV Spectroscopy Of Transition Metal-containing Fluoride And Sulfur-containing Radicals

The spectroscopic characterizations of the transition-metal-containing compounds play an important role in various practical applications such as astrophysics, high temperature chemistry and surface science. On the other hand, the spectral research on sulfur-containing radicals is of great significance in many fields such as combustion chemistry, cosmochemistry and so on. In addition, the study of structure and bonding properties of transition metal containing and sulfur-containing compounds provides important data for the understanding of fundamental chemical reaction processes. This dissertation presents the studies on the spectroscopy of the transition-metal fluorides and the sulfur-containing radicals. The laser-induced fluorescence (LIF) spectrum of the transition-metal fluorides is the principal part in the dissertation. The radicals, such as CoF, TiF and the related sulfur-containing compounds, produced from the metal needles DC discharge and metal plates DC discharge combined with the supersonic jet, were investigated.1. The laser-induced fluorescence (LIF) spectrum of the CoF radicalThe laser-induced fluorescence (LIF) spectrum of jet-cooled CoF has been obtained in the wavelength region of 260-290nm for the first time. Seventeen vibronic bands were observed and assigned to three types transition from the X³Î¦₄ ground state to upper statesΩ'=3,4,5 by rotational analysis. A new vibrational transition with the 0-0 band at 34697.22cm^-1 has been assigned as [34.7]³Î“₅ -X³Î¦₄ transition and effective equilibrium molecular constants for the [34.7]³Î“₅ upper state have been determined. At the same time, a ³Î¦₄-X³Î¦₄ transition and five groupings ofΩ'=3-Ω"=4 transition subbands whose upper states should be a ³Î¦₃ or ³Î”₃ state has been observed. In addition, the lifetime of every band has been measured by monitoring the decay of LIF signal and found the lifetimes of these bands are shorter than 20ns except two bands. On the basis of the spectroscopic data and lifetime measurements, the electronic structures of these possible high-lying electronic states are discussed. 2. The laser-induced fluorescence (LIF) spectrum of the TiF radicalThe laser-induced fluorescence (LIF) excitation spectra of jet-cooled TiF between 245 and 270 nm have been measured for the first time. Six pairs of vibronic bands were observed and assigned to two new transitions [37.8]⁴Φ-X⁴Φand ⁴Δ-X⁴Φ. Rotational analysis has been carried out for the (v'=0-3 to v"=0) vibrational bands of the [37.8]⁴Φ_3/2-X⁴Φ_3/2 and [37.8]⁴Φ_5/2-X⁴Φ_5/2 subbands, also, the two vibrational bands of the ⁴Δ_1/2-X⁴Φ_3/2 and ⁴Δ_3/2-X⁴Φ_5/2 subbands. The effective equilibrium molecular constants for the [37.8] ⁴Φ_5/2 and [37.8] ⁴Φ_5/2 upper states have been determined. At the same time, the lifetimes of the observed bands have been measured by monitoring the decay of LIF signal and found most of these bands have lifetimes in the 30～35ns range except for the (v'+1, 0) vibrational bands of the ⁴Δ_1/2-X⁴Φ_3/2 and ⁴Δ_3/2-X⁴Φ_5/2 subbands. The atomic levels, which are corresponding to the [37.8]⁴Φ-X⁴Φand ⁴Δ-X⁴Φtransitions, are discussed.3. The pilot studied on the spectrum of the sulfur-containing compoundThe sulfur-containing radicals are produced from metal plates DC discharge of the SF₆/Ar mixture along the molecule beam. In the 230-290nm spectral region, three types of new rotational band (a), (b) and (c) have been observed. The (a) bands with only a P branches and an R branches and without Q branches were predicted as the ¹Î£-X¹Î£transition of the SF". The (b) bands conclude three vibrational progressions and the intervals in the same progression are increased in regular. On the other band, the intervals of the bands in the three vibrational progressions, with the same vibrational levels, are similar. By primary analysis, a ³Î -X³Î£transition of the SF⁺ or a transition of a tri-atomic radical will be chose. The (c) bands are the transition bands of an uncertain polyatomic ion. In addition, the interesting influence of the electric field and the additive H₂/O₂/N₂ in the reaction is discussed.