Giant Resonances in Cold Electron Scattering by ${\mathrm{C}\mathrm{S}}_2$

Experimental data are presented for the scattering of cold electrons by ${\mathrm{C}\mathrm{S}}_2$, 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 $50{\AA }^2$ are observed below 100 meV, associated with the transient formation of $\mathrm{C}\mathrm{S}_2{}^{-}$ at 15 meV and with the bend and symmetric stretch of ${\mathrm{C}\mathrm{S}}_2$ 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.

Figure 1

Integral (upper set) and backward cross sections (lower set) for scattering of electrons by ${\mathrm{C}\mathrm{S}}_2$ as a function of electron impact energy. The inset shows the low energy backward scattering data with the background removed (see text).

Figure 2

The ratio of the backward to integral scattering cross sections, $R$, as a function of electron impact energy.