The theory of nuclear electron capture is reviewed in the light of current understanding of weak interactions. Experimental methods and results regarding capture probabilities, capture ratios, and EC/Beta(+) ratios are summarized. Radiative electron capture is discussed, including both theory and experiment. Atomic wave function overlap and electron exchange effects are covered, as are atomic transitions that accompany nuclear electron capture. Tables are provided to assist the reader in determining quantities of interest for specific cases.

Orbital electron capture by the nucleus

A fully analytical description of the allowed β spectrum shape is given in view of ongoing and planned measurements. Its study forms an invaluable tool in the search for physics beyond the standard electroweak model and the weak magnetism recoil term. Contributions stemming from finite size corrections, mass effects, and radiative corrections are reviewed. Particular focus is placed on atomic and chemical effects, where the existing description is extended and analytically provided. The effects of QCD-induced recoil terms are discussed, and cross-checks were performed for different theoretical formalisms. Special attention was given to a comparison of the treatment of nuclear structure effects in different formalisms. Corrections were derived for both Fermi and Gamow-Teller transitions, and methods of analytical evaluation thoroughly discussed. In its integrated form, calculated f values were in agreement with the most precise numerical results within the aimed for precision. The need for an accurate evaluation of weak magnetism contributions was stressed, and the possible significance of the oft-neglected induced pseudoscalar interaction was noted. Together with improved atomic corrections, an analytical description was presented of the allowed β spectrum shape accurate to a few parts in 10-4 down to 1 keV for low to medium Z nuclei, thereby extending the work by previous authors by nearly an order of magnitude.

High precision analytical description of the allowed β spectrum shape

https://deepblue.lib.umich.edu/bitstream/handle/2027.42/32900/0000279.pdf;sequence=1

Detour transitions in internal bremsstrahlung

Plasmon?molecule interactions are widely believed to involve photo-induced interferences between the localized excitation of individual electrons in molecules and the large collective excitation of conduction electrons in metal particles. The intrinsic multi-scale characteristics of plasmon?molecule interactions not only offer great opportunities for realizing precise top-down control of the optical properties of individual molecules, but also allow for accurate bottom-up manipulation of light polarization and propagation as a result of molecular excitation. However, the temporal and spatial complexity of plasmon?molecule experiments severely limits our interpretation and understanding of interactions that have important applications in dye-sensitized solar cells, single-molecule detectors, photoconductive molecular electronics, all-optical switching and photo-catalytic water splitting. This review aims to outline recent progress in experimental practice and theory for probing and exploiting the subtle coupling between discrete molecular orbitals and continuous metallic bands. For each experimental technique or theoretical model, the fundamental mechanisms and relevant applications are discussed in detail with specific examples. In addition, the experimental validation of theoretical models and the computational design of functional devices are both highlighted. Finally, a brief summary is presented together with an outlook for potential future directions of this emerging interdisciplinary research field.

https://iopscience.iop.org/article/10.1088/0034-4885/75/9/096402/pdf

Experimental and theoretical studies of plasmon?molecule interactions

A simple relation for the Fermi function, correct to one per cent, is deduced using the tabulated values of Rose (1955).

https://iopscience.iop.org/article/10.1088/0305-4616/11/3/014/pdf

G.E. Uhlenbeck

Papers

Emission of gamma radiation during the beta decay of nuclei