Electron screening effects in nuclear reactions: still an unsolved problem
Electron screening for nuclear reactions in metals plays an unexpected and important role in enhancing reaction cross sections in the ultra-low energy region. Even though there are still some discrepancies between experimental data from different authors, the enhanced screening effect in metallic environments is well established, and attributed to the quasi-free valence electrons in the […]
A Molecular Perspective on Lithium–Ammonia Solutions
A detailed molecular orbital (MO) analysis of the structure and electronic properties of the great variety of species in lithium–ammonia solutions is provided. In the odd-electron, doublet states we have considered: e−@(NH3)n (the solvated electron, likely to be a dynamic ensemble of molecules), the Li(NH3)4 monomer, and the [Li(NH3)4+ ⋅ e−@(NH3)n] ion-pairs, the Li 2s electron enters a diffuse orbital […]
7Li(p,n) NUCLEAR DATA LIBRARY FOR INCIDENT PROTON ENERGIES TO 150 MEV
Researchers at Los Alamos National Laboratory are considering the possibility of using the Low Energy Demonstration Accelerator, constructed at Los Alamos Neutron Science Center for the Accelerator Production of Tritium Project, as a neutron source. Evaluated nu- clear data are needed for the p+7Li reaction, to predict neutron production from thin and thick lithium tar- […]
Structural Studies of Ammonia and Metallic Lithium-Ammonia Solutions
The technique of hydrogen/deuterium isotopic substitution has been used to extract detailed information concerning the solvent structure in pure ammonia and metallic lithium-ammonia solutions. In pure ammonia we find evidence for approximately 2.0 hydrogen bonds around each central nitrogen atom, with an average N-H distance of 2.4 Å. On addition of alkali metal, we observe […]
Electron Tunneling in Lithium Ammonia Solutions Probed by Frequency-Dependent Electron-Spin Relaxation Studies
Electron transfer or quantum tunneling dynamics for excess or solvated electrons in dilute lithium- ammonia solutions have been studied by pulse electron paramagnetic resonance (EPR) spectroscopy at both X- (9.7 GHz) and W-band (94 GHz) frequencies. The electron spin-lattice (T1) and spin-spin (T2) relaxation data indicate an extremely fast transfer or quantum tunneling rate of […]
Heavy Rydberg states
This paper discusses the nature of heavy Rydberg states, i.e. quantum states in molecular systems that are bound by the almost pure Coulomb potential between pairs of ions. A theoretical framework is developed in terms of mass-scaling laws for heavy Rydberg systems of certain reduced mass, so that the physics of electronic Rydberg states can […]
Recent advances in Rydberg physics using alkaline-earth atoms
In this brief review, the opportunities that the alkaline-earth elements offer for studying new aspects of Rydberg physics are discussed. For example, the bosonic alkaline-earth isotopes have zero nuclear spin which eliminates many of the complexities present in alkali Rydberg atoms, permitting simpler and more direct comparison between theory and experiment. The presence of two […]
Energy Confinement Time in a Magnetically Confined Thermonuclear Fusion Device
In the pursuit of viable nuclear fusion powered energy generation via magneticallyconfined fusion theory and experimentation, the single most important scientific questionmay be energy confinement time in a fusion plasma. In response, a simple theory is presentedfor quantitative calculations of the confinement times of plasma thermal energies inmagnetically confined thermonuclear fusion reactors. The theory is […]
Explosion Dynamics of Rare Gas Clusters in Strong Laser Fields
We have studied the ionic outcome from the interaction of intense laser light with large argon and xenon clusters. Ions with initial energies of several 100 keV are charge and energy selected using a magnetic deflection time-of-flight mass spectrometer. For argon clusters, Coulomb repulsion is the key process in the explosion mechanism, whereas for xenon […]
A brief history of nuclear fusion
Since the 1950s, international cooperation has been the driving force behind fusion research. Here, we discuss how the International Atomic Energy Agency has shaped the field and the events that have produced fusion’s global signature partnership. By Matteo Barbarino At the Second United Nations Conference on the Peaceful Uses of Atomic Energy held in Geneva, […]