Multiple scattering approach to elastic electron collisions with molecular clusters

We revisit our multiple-scattering method to treat low energy elastic electron collisions with (H2O)2. Calculations are performed for different geometries of the water dimer with different dipole moments. The effect of the dipole moment of the cluster is analysed. The elastic cross sections are compared to R-matrix results. Good agreement is found above 1 eV for all geometries. Results conrm the validity of the technique

Elastic electron scattering from 3-hydroxytetrahydrofuran: experimental and theoretical studies

We report the results of measurements and calculations for elastic electron scattering from 3-hydroxytetrahydrofuran (C4H8O2). The measurements are performed with a crossed electron-target beam apparatus and the absolute cross-sections are determined using the relative flow technique. The calculations are carried out using the Schwinger multichannel method in the static-exchange plus polarization (SEP) approximation. A set of angular differential cross-sections (DCS) is provided at five incident energies (6.5, 8, 10, 15 and 20 eV) over an angular range of 20–130°, and the energy dependence of the elastic DCS at a scattering angle of 120° is also presented. Integral elastic and elastic momentum transfer cross-sections have also been derived and calculated. The results are compared with those of recent measurements and calculations for the structurally similar molecule tetrahydrofuran (C4H8O)

Multiple scattering approach to low-energy electron collisions with the water dimer

Multiple scattering theory is applied to low-energy electron collisions with a complex target formed of two molecular scatterers. The total T-matrix is expressed in terms of the T-matrix for each isolated molecule. We apply the approach to elastic electron-(H2O)2 collisions. Following the method developed in our previous work on crystalline ice, we impose a cut-off on the dipole outside the R-matrix sphere and an energy dependent cut-off on the angular momentum components of the monomer T-matrix. An R-matrix calculation of electron-dimer collisions is performed in order to evaluate the accuracy of the multiple scattering approach. The agreement between the two calculations is very good.Comment: 15 pages, 4 figures New submission: Added references Included PACS numbers Figure 3 slightly changed Additions made to the Conclusions and Discussion sectio

Commensurate-incommensurate transitions of quantum Hall stripe states in double-quantum-well systems

In higher Landau levels (N>0) and around filling factors nu =4N+1, a two-dimensional electron gas in a double-quantum-well system supports a stripe groundstate in which the electron density in each well is spatially modulated. When a parallel magnetic field is added in the plane of the wells, tunneling between the wells acts as a spatially rotating effective Zeeman field coupled to the ``pseudospins'' describing the well index of the electron states. For small parallel fields, these pseudospins follow this rotation, but at larger fields they do not, and a commensurate-incommensurate transition results. Working in the Hartree-Fock approximation, we show that the combination of stripes and commensuration in this system leads to a very rich phase diagram. The parallel magnetic field is responsible for oscillations in the tunneling matrix element that induce a complex sequence of transitions between commensurate and incommensurate liquid or stripe states. The homogeneous and stripe states we find can be distinguished by their collective excitations and tunneling I-V, which we compute within the time-dependent Hartree-Fock approximation.Comment: 23 pages including 8 eps figure

Electron scattering from molecules and molecular aggregates of biological relevance

In this Topical Review we survey the current state of the art in the study of low energy electron collisions with biologically relevant molecules and molecular clusters. We briefly describe the methods and techniques used in the investigation of these processes and summarise the results obtained so far for DNA constituents and their model compounds, amino acids, peptides and other biomolecules. The applications of the data obtained is briefly described as well as future required developments

Plasma–liquid interactions: a review and roadmap

Plasma–liquid interactions represent a growing interdisciplinary area of research involving plasma science, fluid dynamics, heat and mass transfer, photolysis, multiphase chemistry and aerosol science. This review provides an assessment of the state-of-the-art of this multidisciplinary area and identifies the key research challenges. The developments in diagnostics, modeling and further extensions of cross section and reaction rate databases that are necessary to address these challenges are discussed. The review focusses on non-equilibrium plasmas

Low-energy electron collisions with tetrahydrofuran

We have performed calculations for electron collisions with tetrahydrofuran (THF) using the UK molecular R-matrix codes. This is the largest molecule ever treated with the R-matrix method, and the only biologically relevant molecule of this size studied theoretically in the inelastic regime. We report ab initio integral cross section for incident energies up to 10 eV. No shape resonances have been found for this system, but a few core-excited resonances are present

WiHArD: Wikipedia based Hierarchical Arabic Dataset

WiHArD (Wikipedia based Hierarchical Arabic Dataset) is a hierarchical Arabic dataset of 6027 texts extracted from Wikipedia Web site. WiHArD is structured into three "level 1" classes and nine "level 2" classes:•"Level 1" classes are Culture (ثقافة), History (تاريخ) and Math (رياضيات). Texts in this level describe general notions related to these domains.•"Level 2" classes are Clothes (ملابس), Food_drinks (طعام و شراب), Tourism (سياحة), Events (أحداث), Inventions (اختراعات), Monuments (أثار), Algebra (جبر), Analysis (تحليل) and Geometry (هندسة). Texts in this level describe specific notions related to these sub-domains.Four files are shared for the benefit of the NLP and IA communities, especially researchers working on Arabic language:1.WiHArD_Directory_Hierarchy.zip contains the directory hierarchy.2.WiHArD.csv, a CSV file of three columns: "text" column contains the Arabic texts; "category_path" and "category_code" columns contain respectively the category path and the category code.3.WiHArD_Level1.csv, a CSV file restricted to the texts the first level, namely Culture (ثقافة), History (تاريخ) and Math (رياضيات).4.WiHArD_Level2.csv, a CSV file restricted to the texts of the second level, namely Clothes (ملابس), Food_drinks (طعام و شراب), Tourism (سياحة), Events (أحداث), Inventions (اختراعات), Monuments (أثار), Algebra (جبر), Analysis (تحليل) and Geometry (هندسة)