Experimental evidence for a virtual state in a cold collision: Electrons and carbon dioxide

Markov Chain Monte Carlo Effective Range Analysis of Low-Energy Electron Elastic Scattering from Xenon

“…The comparison of e − +Xe scattering lengths determined experimentally or theoretically by different methods is given in Table 2. The relatively large negative s-wave scattering length obtained in the present and previous works supports the presence of virtual state enhancing the scattering cross-sections in the limit of zero energy [36].…”

Resonance and Threshold Phenomena in Low-Energy Electron Collisions with Molecules and Clusters

“…http://doc.rero.ch Estrada and Domcke, 1985;Morgan, 1998) and recently also been confirmed by total scattering studies at very low energies (Field et al, 2001b).…”

“…The first is around the 2 Å u shape resonance at 3.6 eV, where boomerang structures have long been known (Boness and Schulz, 1974). The second is dominated by a virtual state below 2 eV (Morrison, 1982;Herzenberg, 1984;Estrada and Domcke, 1985;Kochem et al, 1985;Morgan, 1998;Rescigno et al, 1999;Mazevet et al, 2001;Field et al, 2001b). The virtual state causes dramatic enhancement of the cross-section near threshold for the excitation of the symmetric stretch vibration (100), Fermi-coupled with two quanta of the bending vibration (02 0 0) (Kochem et al, 1985;Field et al, 1991b;Allan, 2001a).…”

“…This conclusion is confirmed by analysis of experimental results and theoretical calculations of low-energy electron scattering by CO 2 and N 2 O molecules. Cross-sections for low-energy electron scattering by CO 2 are rapidly increasing towards lower energies (Morrison et al, 1982;Field et al, 2001b) approaching 200 Â 10 À20 m 2 which corresponds to a large negative scattering length whose value lies between À7.2 a 0 and À6.3 a 0 (Fabrikant, 1984;Mazevet et al, 2001;Field et al, 2001b). On the other hand, experimental (Szmytkowski et al, 1984) and theoretical (Sarpal et al, 1996;Winstead and McKoy, 1998) data on electron scattering by the N 2 O molecule show that the low-energy cross-section in this case is much smaller and does not exceed 8 Â 10 À20 m 2 below E ¼ 1 eV.…”

Dynamics of Low-Energy Electron Attachment to Formic Acid

“…We believe that at geometries where it is slightly unbound it has the character of a virtual state [17], which partially explains the large rise in the fixed-nuclei cross section at low energies [18]. The situation is complicated by the fact that formic acid is a polar molecule and the long-range electron-dipole interaction also leads to large cross sections at low energies.…”