Semiclassical two-step model for ionization of hydrogen molecule by strong laser field

We extend the semiclassical two-step model for strong-field ionization that describes quantum interference and accounts for the Coulomb potential beyond the semiclassical perturbation theory to the hydrogen molecule. In the simplest case of the molecule oriented along the polarization direction of a linearly polarized laser field, we predict significant deviations of the two-dimensional photoelectron momentum distributions and the energy spectra from the case of atomic hydrogen. Specifically, for the hydrogen molecule the electron energy spectrum falls off slower with increasing energy, and the holographic interference fringes are more pronounced than for the hydrogen atom at the same parameters of the laser pulse.Comment: 9 pages, 6 figure

Transfer learning, alternative approaches, and visualization of a convolutional neural network for retrieval of the internuclear distance in a molecule from photoelectron momentum distributions

We investigate the application of deep learning to the retrieval of the internuclear distance in the two-dimensional H$_2^{+}$ molecule from the momentum distribution of photoelectrons produced by strong-field ionization. We study the effect of the carrier-envelope phase on the prediction of the internuclear distance with a convolutional neural network. We apply the transfer learning technique to make our convolutional neural network applicable to distributions obtained for parameters outside the ranges of the training data. The convolutional neural network is compared with alternative approaches to this problem, including the direct comparison of momentum distributions, support-vector machines, and decision trees. These alternative methods are found to possess very limited transferability. Finally, we use the occlusion-sensitivity technique to extract the features that allow a neural network to take its decisions.Comment: 28 pages, 7 figures, 1 tabl

Semiclassical two-step model for strong-field ionization

We present a semiclassical two-step model for strong-field ionization that accounts for path interferences of tunnel-ionized electrons in the ionic potential beyond perturbation theory. Within the framework of a classical trajectory Monte-Carlo representation of the phase-space dynamics, the model employs the semiclassical approximation to the phase of the full quantum propagator in the exit channel. By comparison with the exact numerical solution of the time-dependent Schr\"odinger equation for strong-field ionization of hydrogen, we show that for suitable choices of the momentum distribution after the first tunneling step, the model yields good quantitative agreement with the full quantum simulation. The two-dimensional photoelectron momentum distributions, the energy spectra, and the angular distributions are found to be in good agreement with the corresponding quantum results. Specifically, the model quantitatively reproduces the fan-like interference patterns in the low-energy part of the two-dimensional momentum distributions as well as the modulations in the photoelectron angular distributions.Comment: 31 pages, 7 figure

Study of the Forces Acting on the Animal in the Installation for Fixing with Veterinary Treatments

The study of the forces acting on the animal in the installation for fixing with veterinary treatments. The most time consuming processes in service animals are zootechnical and veterinary treatment of sheep. During the year, it is necessary to carry out more than ten such treatments of each animal, which requires a lot of labor. Almost all animal treatments such as feed to the operator’s workplace and their fixation in a convenient position for him requires significant physical effort of the operator. Therefore, today the technologies and technical means should be created to reduce labor costs for various treatments. The relevance of the problem is due to the lack of theoretical foundations and experimental data for the creation of technological equipment for fixing sheep in zootechnical and veterinary treatments. The purpose of the study is the theoretical and experimental justification of the installation for fixing sheep in zootechnical and veterinary treatments with the justification of the existing efforts on the animal, excluding injury. Developed installation and presented a scheme with two of the conveyor belts forming the grooved shape When designing the installation, the main focus was on the justification of structural elements and modes of operation from the viewpoint of eliminating the possibility of injury to the animal. The experimental studies have confirmed the correctness of the obtained analytical dependences. The obtained results will enable designers to create equipment for the fixation of sheep at the zootechnical and veterinary treatments, precluding injury to the animal and reducing labor costs

Multielectron effect in strong-field ionization of CO

We investigate the effects of the multielectron polarization of the ion described by the induced dipole potential in photoelectron momentum distributions produced in ionization of the CO molecule by a strong laser field. We present results of the numerical solution of the time-dependent Schr\"{o}dinger equation in three spatial dimensions and semiclassical simulations accounting for quantum interference. We predict the change of the asymmetry and interference patterns in two-dimensional photoelectron momentum distributions as well as longitudinal momentum distributions. By using a semiclassical model we identify the mechanism responsible for the observed effects. It is shown that the modifications of electron momentum distributions are caused by a combined effect of the force acting on photoelectrons due to the induced dipole potential and the linear Stark-shift of the ionization potential.Comment: 28 pages, 10 figure

Petroleum desalting by electrically pulverized rinsing water

A method of preparing petroleum and rinsing water emulsion using electric pulverization is described. The influence of various factors on the process of electric pulverization was studied in laboratory electropulverizing devices (EPD) with different lay out and configuration of electrodes. It is shown that by increasing electric field intensity, the size of water drops introduced into petroleum can be varied from a hundred to several micrometers with high degree of their monodispersion. It is ascertained that with an increase in electric conductivity the mean diameter of water drops reduces insignificantly. The emulsion dispersion does not depend on petroleum electric coductivity. With a decrease in interphase tension the mean size of drops in dispersed phase decreases. The possibility to improve petroleum desalting using EPD with required distribution of rinsing water drops over sizes is confirmed