A5038629116- Atomic and Molecular Physics
- Advanced Chemical Physics Studies
- Nuclear physics research studies
- X-ray Spectroscopy and Fluorescence Analysis
- Electron and X-Ray Spectroscopy Techniques
- Advanced Physical and Chemical Molecular Interactions
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum and Classical Electrodynamics
- Crystallography and Radiation Phenomena
- Radiative Heat Transfer Studies
- Mass Spectrometry Techniques and Applications
- Orthopedic Surgery and Rehabilitation
- Laser-induced spectroscopy and plasma
- Astro and Planetary Science
- Quantum Mechanics and Applications
- Muon and positron interactions and applications
- Quantum Chromodynamics and Particle Interactions
- Matrix Theory and Algorithms
- Atomic and Subatomic Physics Research
- Congenital limb and hand anomalies
- Nuclear Physics and Applications
- History and advancements in chemistry
- High-pressure geophysics and materials
- Numerical methods in inverse problems
- Scientific Measurement and Uncertainty Evaluation
University of Oxford
2010-2023
University of Leicester
2023
Cambridge University Hospitals NHS Foundation Trust
2012-2023
Wits University Donald Gordon Medical Centre
2023
University of the Witwatersrand
2016-2023
Addenbrooke's Hospital
2003-2022
University of Cambridge
1982-2022
Public Health Scotland
2022
Spire Cambridge Lea Hospital
2021
Johannesburg Hospital
2016
Abstract The current state of the art in relativistic calculation atomic structures is surveyed. theory modelled on practice non-relativistic calculations, using many-particle wave functions built from Dirac central field spinors. Hamiltonian includes quantum electrodynamic effects form Breit approximation for interaction energy two electrons. Within limits which this valid, it possible to construct matrices one- and two-particle operators hence perform structure calculations automatically...
The gauge invariance of the matrix elements electromagnetic interaction is a property that usually taken for granted. author describes unified derivation in which dependence on potentials are written exhibited explicitly. necessary and sufficient condition transition matrices all multipoles to be invariant longitudinal photons should vanish identically. This imposes conditions initial final wavefunctions automatically satisfied single-particle model but may not necessarily hold in, say,...
Somatic mutations in the phosphatidylinositol/AKT/mTOR pathway cause segmental overgrowth disorders. Diagnostic descriptors associated with PIK3CA include fibroadipose (FAO), Hemihyperplasia multiple Lipomatosis (HHML), Congenital Lipomatous Overgrowth, Vascular malformations, Epidermal nevi, Scoliosis/skeletal and spinal (CLOVES) syndrome, macrodactyly, megalencephaly Megalencephaly‐Capillary malformation (MCAP) syndrome. We set out to refine understanding of clinical spectrum natural...
The equations of the relativistic self-consistent field, first set up by Swirles (1935), are discussed using algebra tensor operators. coefficients radial integrals in formula for energy can be written terms Clebsch-Gordon and Racah coefficients, so that their symmetries easily seen numerical values calculated with use published tables. magnetic interaction between two electrons is considered as well electrostatic interaction, effect this term on ionization a K electron mercury computed...
Tables of X-ray scattering factors for naturally occurring elements and ions have been calculated using a multiconfiguration Dirac–Fock code. The complete data set takes up about 250 kbytes space. For accurate values, it is preferable to interpolate directly. consistency with previous work, parametric fits are also presented error estimates range validity. limiting values the electron factor as sinθ/λ tends zero, which needed calculate mean inner potential scattering, tabulated. results show...
Collision strengths for the low-energy scattering of electrons by Fe XXIII and VII have been calculated using Dirac R-matrix method. For results excitation from ground state (1s22s2)1Se0 to third level (1s22s2p) 3Po1 compared with earlier Breit-Pauli non-relativistic calculations. The agreement is found be good as expected since relativistic effects are important but not dominant. VII, excitations between first nine levels considered a comparison made an distorted-wave calculation. These...
The full transverse interaction generally has not been computed in atomic structure calculations, though relevant formulae have appeared the literature. paper describes an economical algorithm which requires little more effort than simpler for Breit interaction. Examples are given to validate method.
This paper sets out a formal theory of radiative transfer in one-dimensional scattering media arbitrary physical constitution. The is based on an extension the treatment Redheffer, which response layer thickness to fluxes incident its boundaries described by certain linear operator. Juxtaposition two such layers gives third layer, whose operator can be related those constituents operation designated as star product. It shown that this set operators constitutes semigroup under product, and...
grasp is a software package in Fortran 95, adapted to run parallel under MPI, for research atomic physics. The basic premise that, given wave function, any observed property can be computed. Thus, the first step always determine function. Different properties challenge accuracy of function different ways. This distributed MIT Licence.
The Breit interaction which gives the leading correction to Coulomb potential in quantum electrodynamics, is required for precision calculations of binding energies inner electrons heavy atoms multiplet structure, and other applications. correct form use multi-configuration discussed, angular momentum reduction a sum radial integrals carried out completely an approximation valid all problems except those involving very tightly bound electrons. coefficients are presented suitable computation;...
A systematic study of finite dimensional matrix approximations to products quantum mechanical operators is made. It shown that the representation product two equal each if domains matrices are suitably chosen. The importance these results relativistic molecular structure calculations and perturbation theory studies emphasised.
It is argued that the Breit interaction can be included in self-consistent-field procedure of Dirac-Hartree-Fock calculations, and need not necessarily treated as a first-order perturbation, widely believed. The matrix equations including frequency-independent are presented discussed. Prototype calculations for helium-like beryllium-like ions presented.
The relative importance of the direct and indirect relativistic effects on behaviour atomic valence electrons in Dirac-Fock scheme is investigated for ground configurations gold, thallium lutetium which give information s, p, d orbitals. effect, always found to contract orbital, completely responsible contraction 6s orbital effect become progressively smaller order s>p>d approximately d; none systems studied negligible. expand increases according s<p<p<d d. consequences results calculations...
The construction of variational approximations to the solutions Dirac equation is discussed. importance imposing physical boundary conditions for both point- and finite-nuclear models on set trial functions emphasised. low-frequency Breit interaction shown cause no failure when included in iterative Dirac-Hartree-Fock equations. practical advantages calculations which variationally include over conventional treatments employ only Coulomb are Manybody perturbation theory radial correlation...