A5076840514- Atomic and Molecular Physics
- Advanced Chemical Physics Studies
- X-ray Spectroscopy and Fluorescence Analysis
- Mass Spectrometry Techniques and Applications
- Electron and X-Ray Spectroscopy Techniques
- Laser-Matter Interactions and Applications
- Spectroscopy and Quantum Chemical Studies
- Photochemistry and Electron Transfer Studies
- Muon and positron interactions and applications
- Atmospheric Ozone and Climate
- Spectroscopy and Laser Applications
- Radiation Therapy and Dosimetry
- Laser-induced spectroscopy and plasma
- Molecular Junctions and Nanostructures
- Diamond and Carbon-based Materials Research
- History and advancements in chemistry
- Statistical and numerical algorithms
- Inorganic Fluorides and Related Compounds
- Astro and Planetary Science
- Atomic and Subatomic Physics Research
- High voltage insulation and dielectric phenomena
- Spectroscopy Techniques in Biomedical and Chemical Research
- DNA and Nucleic Acid Chemistry
- Advanced Materials Characterization Techniques
- Radiation Effects and Dosimetry
The Open University
2015-2024
Universidad Autónoma de Madrid
1996-2021
Comenius University Bratislava
2020
Universidade Aberta
2020
Hong Kong Metropolitan University
2014
Université de Sherbrooke
2007
University College London
2001-2006
UCL Australia
2005
Electron scattering cross sections for pyridine in the energy range 0–100 eV, which we previously measured or calculated, have been critically compiled and complemented here with new measurements of electron loss spectra double differential ionization sections. Experimental techniques employed this study include a linear transmission apparatus reaction microscope system. To fulfill transport model requirements, theoretical data recalculated within our independent atom screening corrected...
In this Topical Review we survey the current state of art in study low energy electron collisions with biologically relevant molecules and molecular clusters. We briefly describe methods techniques used investigation these processes summarise results obtained so far for DNA constituents their model compounds, amino acids, peptides other biomolecules. The applications data is described as well future required developments.
Strong laser pulses enable probing molecules with their own electrons. The oscillating electric field tears electrons off a molecule, accelerates them, and drives them back toward parent ion within few femtoseconds. are then diffracted by the molecular potential, encoding its structure dynamics angstrom attosecond resolutions. Using elliptically polarized pulses, we show that laser-induced electron diffraction is sensitive to chirality of target. selectively ionizes given orientation along...
A procedure for the ab initio study of electron–molecule collisions at intermediate energies is presented in detail. The molecular R-matrix with pseudostates method based on inclusion discretized continuum states close-coupling expansion. This allows, first time, calculation totally cross sections electron impact ionization molecules as well electronic excitation above threshold. general and can be applied to multielectron targets. Results H+3 H2 are presented. Numerical considerations...
We have performed calculations for electron collisions with tetrahydrofuran (THF) using the UK molecular R-matrix codes. This is largest molecule ever treated method, and only biologically relevant of this size studied theoretically in inelastic regime. report ab initio integral cross section incident energies up to 10 eV. No shape resonances been found system, but a few core-excited are present.
We present theoretical elastic and electronic excitation cross sections experimental for electron collisions with pyrimidine. use the R-matrix method to determine integral differential inelastic energies up 15 eV. The have been determined in 15–50 eV impact energy range. Typically, there is quite reasonable agreement between sections. Calculated agree very well prior results.
Collisions of low energy electrons with molecules are important for understanding many aspects the environment and technologies. Understanding processes that occur in these types collisions can give insights into plasma etching processes, edge effects fusion plasmas, radiation damage to biological tissues more. A radical update previous expert system computing observables relevant Quantemol-N, is presented. The new Quantemol Electron Collision (QEC) simplifyies user experience, improving...
The R-matrix method is used to calculate dissociative excitation cross sections for the four lowest-lying electronically excited states of H2O in energy range 5-15 eV. For first time calculations are performed taking into account nuclear motion by means an adaptation adiabatic nuclei approximation. Cross compared with previous and new fixed-nuclei results also experiments. Resonance positions widths calculated different geometries water molecule.
Total electron-${\mathrm{H}}_{2}\mathrm{O}$ scattering cross sections have been measured from 50 to $5000\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ with experimental errors of about 5%. Integral elastic and inelastic calculated over a broad energy range $(1--10\phantom{\rule{0.2em}{0ex}}000\phantom{\rule{0.3em}{0ex}}\mathrm{eV})$ an optical potential method assuming independent atom representation. Dipole rotational excitations also included in the framework first Born approximation. From...
Rotational excitation of H2O, HDO and D2O by thermal electron impact is studied using the molecular R-matrix method. Rate coefficients are obtained up to temperatures 8000 K. De-excitation rates critical densities also given. It shown that dominant transitions those for which ΔJ= 0, ±1, as predicted dipolar Born approximation. However, a pure treatment found overestimate cross-sections close threshold energies neglect important (dipole forbidden) transitions, owing importance short-range...
Differential, integral and momentum transfer cross sections for the vibrationally elastic rotationally inelastic scattering of electrons from water at low collision energies (E < 7 eV) are reported. The R-matrix method is used to compute body-fixed T-matrices while calculations performed within fixed-nuclei approximation corrected with standard Born-closure formula. Our compared very recent experimental results Cho et al (2003 Radiat. Phys. Chem. 68 115). differential in good agreement...
A new procedure is presented for the ab initio study of electron–molecule collision at energies straddling target ionization threshold. The R-matrix with pseudostates method, which allows inclusion discretized continuum states in a close-coupling expansion, adapted to molecular targets using even-tempered basis sets. Calculations electron collisions H+3 ion provide converged polarizabilities, electronic excitation and cross sections.
Low-energy electron (LEE) scattering with alcohols is important for understanding radiation damage in biological systems and atmospheric processes. Here, we investigate LEE from methanol (CH3OH), the simplest alcohol. For this purpose, have performed ab initio R-matrix calculations within fixed-nuclei approximation incident energies up to 12 eV. Elastic electronic excitation cross sections show presence of three core-excited resonances 6?12 eV range accordance reported experimental results....
We present a comprehensive ab-initio study of electron collisions with pyrazine, pyrimidine, and pyridazine. The emphasis is placed on the identification characterization resonances in these systems. use R-matrix method show that analysing time-delay reveals whose signature not visible eigenphase sums. In addition to well known π* below 5 eV, we find three core-excited shape energy range 5.5–8.5 eV few Feshbach dipolar molecules. Additionally, 11 little effect elastic scattering from ground...
We present results of ab-initio scattering calculations for electron collisions with pyrazine using the R-matrix method, carried out at various levels approximation. confirm existing experimental and theoretical understanding three well-known π* shape resonances. In addition, we find numerous core-excited resonances (above 4.8 eV) identify their most likely parent states. also differential cross sections, showing high sensitivity to model chosen low energies. make recommendations regarding...
Low-energy dissociative electron attachment (DEA) to the CF2Cl2 and CF3Cl molecules in a water cluster environment is investigated theoretically. Calculations are performed for trimer hexamer. It shown that DEA cross section strongly enhanced when attaching molecule embedded cluster, this grows as number of increases. This growth explained by trapping effect due multiple scattering while trapped environment. The increases resonance lifetime negative ion survival probability. confirms...
We employ the recently developed multi-photon R-matrix method for molecular above-threshold photoionization to obtain second-order ionization amplitudes that govern interference in RABITT experiments. This allows us extract time delays are better agreement with non-perturbative time-dependent simulations of this process than typically used combination first-order (Wigner) and asymptotic corrections. calculate molecular-frame as well orientation-averaged H$_2$, N$_2$, CO$_2$, H$_2$O N$_2$O...
We describe an implementation of the vibro-rotational sudden approximation eikonal (SEIKON) method to treat collisions between ions (atoms) and diatomic molecules at impact energies such that a semiclassical can be applied relative motion colliding species, close-coupling molecular expansion is able accurately represent electronic transitions. Our method, which does not make use Franck - Condon-type approximations, allows us evaluate vibrationally resolved charge-transfer excitation cross...
Total electron scattering cross sections for pyrazine in the energy range 10-500 eV have been measured with a new magnetically confined transmission-beam apparatus. Theoretical differential and integral elastic, as well inelastic, calculated by means of screening-corrected form independent-atom representation (IAM-SCAR) from 10 to 1000 incident energies. The present experimental theoretical total show good level agreement, within 10%, overlapping range. Consistency these results previous...
We measured differential cross sections for electron-impact electronic excitation of pyrimidine, both as a function electron energy up to 18 eV, and scattering angle 180°. The emphasis the present work is on recording detailed functions revealing resonances in process. were summed obtain integral sections. These are compared results R-matrix calculations, which successfully reproduce magnitude section major resonant features. Comparison experiment calculated contributions different...