Low-energy electron impact spectroscopy of OCS and CS2

Dissociative electron attachment dynamics of carbon disulfide and violation of axial recoil approximation near 6 eV resonance

Complete dissociation dynamics of low-energy electron attachment to carbon disulfide have been studied using the velocity slice imaging (VSI) technique. The ion yields of the different fragment anions produced due to the dissociative electron attachment to carbon disulfide for the 5 to 11 eV incident electron energy range have been collected. Two resonances for S^- ions are observed at around 6.2 eV and 7.7 eV, while only one resonance for both the CS^- and S₂^- ions at 6.2 eV is present in this energy range. The kinetic energy and the angular distributions of these fragment negative ions at different incident electron energies around the 6.2 eV resonance have been extracted from the velocity slice images. These experimentally obtained angular distributions of different fragment anions combined with previous theoretical calculations provide a detailed picture of the breakdown of axial recoil approximation and the complete dissociation dynamics involved in this resonance.

Fragmentation dynamics of CS2 in collisions with 1.0 keV electrons

The dissociation dynamics of CS₂ molecules in collisions with 1.0 keV electrons is studied. We observe a series of two- and three-body fragmentation channels which are identified from the correlation map between fragment ions. For all of the channels, the kinetic energy release (KER) distributions are obtained. The Dalitz plot and Newton diagram are adopted to analyze the fragmentation dynamics of the three-body dissociation channels. For C S 2 3 + and C S 2 4 + , both the concerted and sequential fragmentation mechanisms are observed where the concerted mechanism dominates. For C S 2 5 + , only the concerted mechanism is observed. Two types of Coulomb explosion models considering the molecular vibration are adopted to simulate the experimental KER distributions of the three-body channels. While obvious deviations are observed considering each ion during the whole dissociation process with an integer charge, good agreement can be achieved within deviation less than 5% if the charge state of the ions are adopted from ab initio calculations.

Giant resonances in cold electron scattering by CS(2)

Experimental data are presented for the scattering of cold electrons by CS2, for both integral and backward scattering, between a few meV and a few hundred meV impact energy. Giant resonances with cross sections in excess of 50 A(2) are observed below 100 meV, associated with the transient formation of CS(-)(2) at 15 meV and with the bend and symmetric stretch of CS(2) at thresholds of 49 and 82 meV, respectively. The resonance at 49 meV is 2 orders of magnitude greater in cross section than a dipole impulsive model predicts. These structures are superimposed on a sharp rise in the scattering cross section at low energy, which may be attributed to virtual state scattering.