| The spectral research on sulfur-containing radicals is of great significance in many fields such as atmospheric chemistry, combustion chemistry, cosmochemistry and so on. This dissertation presents the experimental studies on the resonance-enhanced multiphoton ionization (REMPI) excitation spectra of two sulfur-containing diatomic free radicals. The NS and SF radicals were produced by the pulsed dc discharge under the supersonic free jet condition and investigated by REMPI spectroscopy. The main results are summarized as follows:1. REMPI study on NS radicalsThe (1+1) REMPI spectra of N32S and N34S radicals have been recorded in the single-photon wavelength region of 222-280nm. Seven states in all of N32S radicals were investigated in the current range, which were B2âˆ, B'2∑+, A2Δ, G2∑-, C2∑+, H2∠and I2∑-, respectively. By the vibrational analysis and the measurement of isotopic shifts, the observed electronic bands were assigned and identified as follows: three vibrational progressions (v'=0-4, 0), (v'=1-4, 1) and (v'=2-4, 2) of B'2∑+-X2∠transition; (9, 0), (10, 0), (11, 0) and (12, 0) bands of B2âˆ-X2∠transition; three vibrational progressions (v'=0-5, 0), (v'=0-5,1) and (v'=1-5, 2) of A2Δ-X2∠transition; three vibrational progressions (v'=0-1, 0), (v'=0-1, 1) and (v'=0-1, 2) of C'2∑+-X2∠transition; (1, 0) band of G2∑--X2∠transition; (0, 0) and (1, 0) bands of H2âˆ-X2∠transition; and (0, 0), (0, 1), (1, 1), (0, 2), (1, 2) bands of I2∑+-X2∠transition. Most of them were reported for the first time. Rotational simulation leads to yield the rotational constants of these bands and determine more complete and accurate spectroscopic constants for some of the N32S states.In the study on the A state of NS radicals, we have found that the A state assigned as 2Δ state previously appeared obviously to be of ∠symmetry. The NS A state has been reinvestigated and an entire vibrational progression of A-X system has been observed in the range 38400 —45000cm-1, each band of which appeared to be...
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