No Arabic abstract
We have used the convergent close-coupling method and a unitarized first-order many-body theory to calculate integral cross sections for elastic scattering and momentum transfer, for excitation of the 5d^2 ^1S, 6s6p^1P_1, 6s7p^1P_1, 6s8p^1P_1, 6s5d^1D_2, 5d^2^1D_2, 6s6d^1D_2, 6p5d^1F_3, 6s4f^1F_3, 6p5d^1D_2, 6s6p^3P_{0,1,2}, 6s5d^3D_{1,2,3}, and 6p5d^3D_2 states, for ionization and for total scattering by electron impact on the ground state of barium at incident electron energies from 1 to 1000 eV. These results and all available experimental data have been combined to produce a recommended set of integral cross sections.
State-to-state differential cross sections (DCSs) for rotationally inelastic scattering of H2O by H2 have been measured at 71.2 meV (574 cm-1) and 44.8 meV (361 cm-1) collision energy using crossed molecular beams combined with velocity map imaging. A molecular beam containing variable compositions of the (J = 0, 1, 2) rotational states of hydrogen collides with a molecular beam of argon seeded with water vapor that is cooled by supersonic expansion to its lowest para or ortho rotational levels (JKaKc= 000 and 101, respectively). Angular speed distributions of fully specified rotationally excited final states are obtained using velocity map imaging. Relative integral cross sections are obtained by integrating the DCSs taken with the same experimental conditions. Experimental state-specific DCSs are compared with predictions from fully quantum scattering calculations on the most complete H2O-H2 potential energy surface. Comparison of relative total cross sections and state-specific DCSs show excellent agreement with theory in almost all details
A theoretical investigation of the dissociative excitation by electron impact on the NO molecule is presented, aiming to make up for the lack of data for this process in the literature. A full set of vibrationally-resolved cross sections and corresponding rate coefficients are calculated using the Local-Complex-Potential approach and five resonant states of NO^-.
The cross sections of ultra-soft x-ray bremsstrahlung in at electron scattering by Ar, Kr and Xe are theoretically calculated. The results are consistent with the absolute values of the differential cross sections measured by Gnatchenko et al [Phys. Rev. A 80, 022707 (2009)] for scattering electrons with an energy of 600 eV on these atoms.
Recent technological advances allowed the coherent optical manipulation of high-energy electron wavepackets with attosecond precision. Here we theoretically investigate the collision of optically-modulated pulsed electron beams with atomic targets and reveal a quantum interference associated with different momentum components of the incident broadband electron pulse, which coherently modulates both the elastic and inelastic scattering cross sections. We show that the quantum interference has a high spatial sensitivity at the level of Angstroms, offering potential applications in high-resolution ultrafast electron microscopy. Our findings are rationalized by a simple model.
We have systematically investigated the ground-state hyperfine structure for alkali-metal atoms ^{87}Rb, ^{133}Cs, ^{211}Fr and alkali-metal-like ions ^{135}Ba^+, ^{225}Ra^+, which are of particular interest for parity violation studies. The quantum electrodynamic one-loop radiative corrections have been rigorously evaluated within an extended Furry picture employing core-Hartree and Kohn-Sham atomic potentials. Moreover, the effect of the nuclear magnetization distribution on the hyperfine structure intervals has been studied in detail and its uncertainty has been estimated. Finally, the theoretical description of the hyperfine structure has been completed with full many-body calculations performed in the all-orders correlation potential method.