PHYS 570 |
| The photoionization efficiency(PIE) spectra of sulfur (S) atoms in the metastable S(1D) and S(1S) states in the wavelength range of 73,350-84,950 cm-1 have been recorded using tunable vacuum ultraviolet (VUV) laser radiation. The S(1D) and S(1S) atoms are produced by the 193 nm photodissociation of CS2. The PIE spectra of S(1D) and S(1S) thus observed shows 35 autoionizing resonances with little contribution from direct photoionization into the S(4S3/2)+e- ionization continuum. Individual autoionizing Rydberg resonances are identified to originate from S(1D) or S(1S) based on measurements of the velocity-mapped ion image of S+. The analysis and assignment of these Rydberg peaks have revealed 23 new Rydberg states, which have not been characterized in previous studies. The profiles of these well-resolved autoionizing resonances are simulated using the Fano line shape formula, yielding values for the line shape parameters, level energies, and line widths of the autoionizing Rydberg states. The autoionization lifetimes (τ) of the Rydberg states determined using the line widths are found to deviate from the scaling law of τ(n*)∝ n*3, where n* is the effective quantum number of the Rydberg state. This observation can be ascribed to perturbations by nearby Rydberg states, leading to shortening of autoionization lifetimes of the Rydberg levels. |
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PHYS Poster Session - Computational Spectroscopy and Reaction Dynamics
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster
Sci-Mix
Division of Physical Chemistry |