We have investigated the electron scattering from the freely movable spin-1/2 particle in the presence of a linearly polarized laser field in the first Born approximation. The laser-dressed state of electrons is described by a time-dependent wave function which is derived from a perturbation treatment. With the aids of numerical simulations, we explore the dependencies of the differential cross section on the laser field intensity as well as the electron-impact energy. Due to the mobility of the target, the differential cross section of this process is smaller than that of Mott scattering.

A novel strategy for the synthesis of imidazo-fused polycyclic compounds under mild, base-free, and silver-free conditions by a rhodium­(III)-catalyzed C–H annulation of alkenyl or arylimidazoles and (hetero)­cyclic 1,3-dicarbonyl compounds is reported here. Such a step-economic protocol features the selective cleavage of two different C–H bonds in one step, featuring easy operation, readily available starting materials, gram-scale synthesis, broad functional group tolerance, and no requirement to presynthesize carbene precursors. Notably, the synthetic potential is showcased by the structural modification of drug and the highly step-economic synthesis of Janus kinase inhibitor in only three steps with a satisfactory 26% total yield (previous method: in nine steps with 0.6% yield).

The photoionization of a hydrogen atom from its ground state with ultra-fast chirped pulses is investigated by numerically solving the time-dependent Schrödinger equation within length, velocity, and Kramers–Henneberger gauges. Converged results for all gauges for chirp-free pulses agree with the prediction of dynamic interference for ground state hydrogen atoms predicted recently by Jiang and Burgdörfer [Opt. Express 26, 19921 (2018)]. In addition, we investigated photoelectron spectra of hydrogen atoms by chirped laser pulses, and showed that dynamic interference effect will be weaken for pulses with increasing linear chirp. Our numerical results can be understood and discussed in terms of an interplay of photoelectron wavepackets from first and second halves of laser enevelop, including the ac Stark energy level shift of the photoelectron final state and atomic stabilization effect at ultra-high intensities.

In this work, we investigate the Molecular-Frame Photoelectron Momentum and Angular Distributions (MF-PMD and MF-PAD) of H$^+_2$ in the presence of XUV Attosecond Pulses. We present the sensitive alignment effect of MF-PMD and MF-PADs when the laser field polarization and the molecular axis are close to parallel geometry. Results show that the MF-PADs and MF-PMDs of single-photon single ionization of H$^+_2$ ion dramatically change when the alignment slightly shifts from parallel geometry to a small alignment angle (e.g., 1$^{\circ}$) between laser polarized direction and the molecular axis with equilibrium inter-nuclear distance R$_c$=2. As the R$_c$ increase to 4, such sensitivity is decreased. The inter-nuclear distance-dependent transition cross-section to different channels is found to be the origin of such sensitivity.

We perform a theoretical study on dynamic interference in single photon ionization of ground state hydrogen atoms in the presence of a super-intense ultra-fast chirped laser pulse of different chirp types (equal-power and equal-FWHM laser pulses) by numerically solving the time-dependent Schrödinger equation in one dimension. We investigate the influences of peak intensity and chirp parameters on the instantaneous ionization rate and photoelectron yield, respectively. We also compare the photoelectron energy spectra for the ionization by the laser pulses with different chirp types. We find that the difference between the instantaneous ionization rates for the ionization of hydrogen atom driven by two different chirped laser pulses is originated from the difference in variation of vector potentials with time.