Low-energy electrons (<2 eV) can fragment gas phase formic acid (HCOOH) molecules through resonant dissociative attachment processes. Recent experiments have shown that the principal reaction products of such collisions are formate ions (HCOO-) and hydrogen atoms. Using first-principles electron scattering calculations, we have identified the responsible negative ion state as a transient \pi* anion. Symmetry considerations dictate that the associated dissociation dynamics are intrinsically polyatomic: a second anion surface, connected to the first by a conical intersection, is involved in the dynamics and the transient anion must necessarily deform to non-planar geometries before it can dissociate to the observed stable products.

We present the results of ab initio calculations for elastic electron scattering by tetrahydrofuran (THF) using the complex Kohn variational method. We carried out fixed-nuclei calculations at the equilibrium geometry of the target molecule for incident electron energies up to 20 eV. The calculated momentum transfer cross sections clearly reveal the presence of broad shape resonance behavior in the 8-10 eV energy range, in agreement with recent experiments. The calculated differential cross sections at 20 eV, which include the effects of the long-range electron-dipole interaction, are alsofound to be in agreement with the most recent experimental findings.

Electronic structure methods are combined with variational fixed-nuclei electron scattering calculations and nuclear dynamics studies to characterize resonant vibrational excitation and electron attachment processes in collisions between low-energy electrons and CF radicals. Several low-lying negative ion states are found which give rise to strong vibrational excitation and which are expected to dominate the low-energy electron scattering cross sections. We have also studied several processes which could lead to production of negative ions (F- and C-), However, in contrast to other recent predictions, we do not find CF in its ground state to be a significant source of negative ion production when interacting with thermal electrons.

We present the results of an ab initio study of elastic scattering and vibrational excitation of NO by electron impact in the low-energy (0-2 eV) region where the cross sections are dominated by resonance contributions. The 3Sigma-, 1Delta and 1Sigma+ NO- resonance lifetimes are taken from our earlier study [Phys. Rev. A 69, 062711 (2004)], but the resonance energies used here are obtained from new configuration-interaction studies. Here we employ a more elaborate nonlocal treatment of the nuclear dynamics, which is found to remedy the principal deficiences of the local complex potential model we employed in our earlier study, and gives cross sections in better agreement with the most recent experiments. We also present cross sections for dissociative electron attachment to NO leading to groundstate products. The calculations show that, while the peak cross sections starting from NO in its ground vibrational state are very small, the cross sections are extremely sensitive to vibrational excitation of the target and should be readily observable for target NO molecules excited to v = 10 and above.

We present the results of a study of elastic scattering and vibrational excitation of NO by electron impact in the low-energy (0-2 eV) region where the cross sections are dominated by resonance contributions. The ^3\Sigma^-, ^1\Delta and ^1\Sigma^+ NO^- resonance lifetimes are taken from our earlier study [Phys. Rev. A 69, 062711 (2004)], but the resonance energies used here are obtained from new configuration-interaction studies. Here we employ a more elaborate nonlocal treatment of the nuclear dynamics, which is found to remedy the principal deficiencies of the local complex potential model we employed in our earlier study, and gives cross sections in better agreement with the most recent experiments. We also present cross sections for dissociative electron attachment to NO leading to ground state products, \rm O^-(^2\rm P) + \rm N(^4\rm S). The calculations show that, while the peak cross sections starting from NO in its ground vibrational state are very small (\sim 10^-20 \rm cm^2), the cross sections are extremely sensitive to vibrational excitation of the target and should be readily observable for target NO molecules excited to \nu = 10 and above.