Overall and state-specific electronic quenching of atomic sulfur S(3p34p 3P ) by collisions with He (original) (raw)
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Lower excited electronic states of sulfur (S8): A two-photon study by the thermal lensing method
Chemical Physics Letters, 1988
Thermal lensing is applied to the study of multiphoton excitations in sulfur solution and crystal. The polarized two-photon absorption spectrum of sulfur and the polarization ratio for both the solution and crystal have been measured from 3000 to 2500 A (crystal) and to 2200 a (solution). The results are discussed in terms of electronic energy levels and two-photon absorption tensors of molecular sulfur calculated with semi-empirical methods.
Photoionization of the 3s23 p4 3P and the 3s23 p4 1D, 1S states of sulfur: Experiment and theory
Photoionization of neutral atomic sulfur in the ground and metastable states was studied experimentally at a photon energy resolution of 44 meV (full width at half maximum). Relative cross section measurements were recorded by using tunable vacuum ultraviolet radiation in the energy range 9–30 eV obtained from a laser-produced plasma and the atomic species were generated by photolysis of molecular precursors. Photoionization of this atom is characterized by multiple Rydberg series of autoionizing resonances superimposed on a direct photoionization continuum. A wealth of resonance features observed in the experimental spectra are spectroscopically assigned and their energies and quantum defects tabulated. The cross sectionmeasurements are comparedwith state-of-theart theoretical cross section calculations obtained from the Dirac Coulomb R-matrix method. Resonance series in the spectra are identified and compared, indicating similar features in both the theoretical and experimental spectra.
Journal of Physics B: Atomic, Molecular and Optical Physics, 2006
A core-excited sulfur state with a lifetime almost one order of magnitude longer than in molecular 2p core-hole states is selectively produced by ultrafast dissociation of S 2p → σ * excited OCS. Clear evidence for this is provided by strong atomic peaks (20% of the total intensity) in x-ray fluorescence but very weak ones (2%) in the corresponding resonant Auger spectrum. Corroborating the assignment of the spectra, ab initio calculations explain the enhanced lifetime: the Auger decay of the produced 3 D 3 (2p 5 3p 5 ) sulfur state is strongly decreased as it contradicts a newly derived propensity rule of the L 2,3 MM Auger decay.
Fluorescence emission from photo-fragments after resonant S 2p excitations in H 2 S
Visible-UV fluorescence emission of gas-phase hydrogen sulfide, H 2 S, has been studied at the S 2p edge with synchrotron radiation excitation. Dispersed fluorescence measurements in the wavelength range 300–900 nm were taken at several photon energies corresponding to the excitations of the S 2p electrons to the unoccupied molecular and Rydberg orbitals. The spectra reveal fluorescence from the H, S, S + , HS and HS + photo-fragments. H is found to be the strongest emitter at Rydberg excitations, while the emission from S + is dominant at the molecular resonances and above the S 2p ionization thresholds. The intensities of hydrogen Lyman-a (122 nm), Balmer-a (656 nm), Balmer-b (486 nm) transitions as well as the visible-UV total fluorescence yield (300–900 nm) and the total ion yield were measured by scanning the photon energy in small steps across the S 2p edge. The different Balmer lines show some sensitivity to the specific core excitations, which is, however, not so strong as that recently observed in the water molecule [E.
On the electronic excited states of sulfur dioxide
Journal of Molecular Structure: THEOCHEM, 2005
We report Ab Initio calculations for the ground and lowest electronic excited states of sulfur dioxide. Molecular geometries, together with the electric dipole moment, dipole polarizability and first hyperpolarizability are given for each state. Ground state properties were calculated using the HF and B3LYP models, whilst excited states were modelled using CIS and CIS(D). Our results reveal substantial differences between these properties.
arXiv (Cornell University), 2022
Our previous study on dissociative recombination of ground state SH + into 2 Π states of SH is extended by taking into account the contribution of 4 Π states recently explored by quantum chemistry methods. Multichannel quantum defect theory is employed for the computation of cross sections and rate coefficients for dissociative recombination, but also for vibrational excitation. Furthermore, we produce the atomic yields resulting from recombination, quantifying the generation of sulfur atoms in their ground (3 P) and lowest excited (1 D) states respectively.
The Journal of Chemical Physics, 2008
The photoionization efficiency ͑PIE͒ spectra of metastable sulfur ͑S͒ atoms in the 1 D and 1 S states have been recorded in the 73 350-84 950 cm −1 frequency range by using a velocity-mapped ion imaging apparatus that uses a tunable vacuum ultraviolet laser as the ionization source. The S͑ 1 D͒ and S͑ 1 S͒ atoms are produced by the 193 nm photodissociation of CS 2. The observed PIE spectra of S͑ 1 D͒ and S͑ 1 S͒ shows 35 autoionizing resonances with little or no contribution from direct photoionization into the S + ͑ 4 S 3/2 ͒ + e − ionization continuum. Velocity-mapped ion images of the S + at the individual autoionizing Rydberg resonances are used to distinguish whether the lower state of the resonance originates from the 1 D, 1 S, or 3 P states. The analysis and assignment of the Rydberg peaks revealed 22 new Rydberg states that were not previously known. The autoionization lifetimes of the Rydberg states are derived from the linewidths by fitting the lines with the Fano formula. Deviations from the scaling law of ͑n * ͒ ϰ n *3 , where n * is the effective quantum number of the Rydberg state, are observed. This observation is ascribed to perturbations by nearby triplet Rydberg states, which shorten the autoionization lifetimes of the singlet Rydberg levels.
Oscillator strengths for allowed and intercombination transitions in neutral sulfur
We have calculated oscillator strengths and transition probabilities of electric-dipoleÈallowed and intercombination transitions from Ðne-structure levels of the ground 3s23p4 conÐguration to the levels belonging to conÐgurations 3s23p34s, 3s23p35s, 3s23p33d, 3s23p34d of neutral sulfur. Extensive conÐguration-interaction wave functions are used to represent these levels. The relativistic corrections have been included through the Breit-Pauli Hamiltonian. The results are compared with previous theoretical calculations and with measurements.