Alkali halides MX, have been viewed as typical ionic compounds, characterized by 1:1 ratio necessary for charge balance between M(+) and X(-). It was proposed that group I elements like Cs can be oxidized further under high pressure. Here we perform a comprehensive study for the CsF-F system at pressures up to 100 GPa, and find extremely versatile chemistry. A series of CsFn (n ≥ 1) compounds a...

A combined linear-response-frozen electron-density model has been implemented in a molecular-dynamics scheme derived from an extended Lagrangian formalism. This approach is based on a partition of the electronic charge distribution into a frozen region described by Kim-Gordon theory [J. Chem. Phys. 56, 3122 (1972); J. Chem. Phys. 60, 1842 (1974)] and a response contribution determined by the in...

In colored LiF crystals there are many absorption and emission bands which cover a wide region of the spectrum from 200 up to 1 300 nm without breaking the continuity. In the frame of these favourable conditions we have performed some experiments of energy transfer among various color centers. The results indicate the existence of efficient exchanges of radiative energy among several bands by u...

The trapping of electrons by grain boundaries in semiconducting and insulating materials is important for a wide range of physical problems, for example, relating to: electroceramic materials with applications as sensors, varistors and fuel cells, reliability issues for solar cell and semiconductor technologies and electromagnetic seismic phenomena in the Earth's crust. Surprisingly, considerin...

ARSTRACT The interaction between conduction electrons with energies from .25 to 7.5 eV and longitudinal optical phonons in alkali halides is studied in detail by time dependent perturbation theory. Expressions for the rate and angular distribution of scattering are obtained. The electron transport problem is then solved with the exact quantum mechanical scattering results by a direct simulation...

Affinities of alkali cations and halide anions for the peptide group were quantified using molecular dynamics simulations of aqueous solutions of N-methylacetamide using both nonpolarizable and polarizable force fields. Potassium and, more strongly, sodium exhibit an affinity for the carbonyl oxygen of the amide group, while none of the halide anions shows any appreciable attraction for the ami...

The paper deals with several novel approaches to the studies of interactions and dynamics in liquids. A new, flexible time-correlation function is introduced. It has an analytical counterpart in the frequency domain and enables one to fit even badly overlapped vibrational line profiles obtaining dynamical information at the same time. As examples, quantitative description of the interaction pot...

Lyoluminescence, the radiation induced light emission during the dissolution of irradiated solid substances like alkali halides, saccharides, amino acids etc. was proposed as a method of dosimetry. I t is established that lyoluminescence is a consequence of a reaction of radicals from radiolysis wi th oxygen dissolved in the solvent. The role of oxygen in the lyoluminescence of saccharides has ...

The alkali halides sodium fluoride, sodium bromide, and sodium iodide exist in the gas phase as both monomer and dimer species. A reanalysis of gas electron diffraction (GED) data collected earlier has been undertaken for each of these molecules using the EXPRESS method to yield experimental equilibrium structures. EXPRESS allows amplitudes of vibration to be estimated and correction terms to b...

We have studied possible adsorption geometries of neutral NaCl clusters on the disordered surface of a large silicon model tip used in non-contact atomic force microscopy. The minima hopping method was used to determine low energy model tip configurations as well as ground state geometries of isolated NaCl clusters. The combined system was treated with density functional theory. Alkali halides ...