Potential barrier at the NaCl---Si(111) interface

The potential barrier at the NaCl---Si(111) interface has been studied using UPS. It was stated that even a very thin NaCl layer decreases the photoemission threshold of the examined system. A saturation value, equal to 3.4±0.1 eV is obtained for a 15–20 ÅA NaCl layer thickness.     

Experimental evidence of highly energy relaxed products in the 35 MeV/u84Kr+197Au reaction

The Q_β-values of⁹⁹Rb,^99,100Sr and¹⁰⁰Y have been measured for the first time at the mass separator OSTIS of the ILL; for⁹⁹Y,^99,100Zr and¹⁰⁰Nb, the results of earlier experiments were confirmed with reduced experimental errors. The two-neutron binding energies derived from the experimental Q_β-values clearly indicate that the nuclei¹⁰⁰Sr and¹⁰⁰Y are strongly deformed.     

Diffusion of spheres in a concentrated suspension II

We evaluate the wavevector dependent (short-time) diffusion coefficient D(k) for spherical particles in suspension, by extending a previous study of selfdiffusion (which corresponds to the case of large k). Our analysis is valid up to high concentrations and fully takes into account the many-body hydrodynamic interactions between an arbitrary number of spheres, as well as the resummed contributions from a special class of correlations. Results obtained which agree well with available experimental data.     

Total synthesis and properties of prostaglandins. 40. Synthesis ofβ-Oxyaminovinyl bicyclic γ-lactones

Acetylation of oxyiminomethyl bicyclic y-lactones gave the corresponding N-acetyl--oxyaminovinyl derivatives.Latvian Institute of Organic Synthesis, Riga, LV-1006. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 613-615, May, 1995. Original article submitted March 27, 1995.     

Shell-target laser-plasma images in the light of intrinsic and backlit X radiation

Results are presented of calculation of x-ray plasma images of glass shell targets with diagnostic additives Na, K, and Ca in the light of the intrinsic radiation of the resonance lines of H and He ions with Z_n = 8, ii, 14, and 20, and also in the light of cw radiation in the wavelength range = 1-300 Å. The calculation results are compared with laser-plasma images obtained in experiments with the Del'fin-l thermonuclear facility. The temperature and density of the plasma, the rate of corona expansion, the target mass ablation rate, and the hydrodynamic coefficient of laser-energy transfer into kinetic energy of the ablating shell are determined. The plasma images obtained by backlighting the shell target with an auxiliary x-ray source are analyzed with account taken of the radiation refraction. The required energy, temporal, and spectral characteristics of the auxiliary source are determined.Laser-Plasma Laboratory, Lebedev Physics Institute. Translated from Preprint No. 70 of the Lebedev Physics Institute, Academy of Sciences of the USSR, Moscow, 1989.     

HYPERICIN DERIVED TRIPLET STATES and TRANSIENTS IN ALCOHOLS and WATER

Abstract— Direct pulse photoexcitation of an antivirally active compound, hypericin sodium salt in ethanol, results in a short-lived transient, attributed to a triplet state. In the presence of reducing agents, a long-lived transient is observed, which indicates a radical anion species. In isopropanol solution, an identical triplet state is formed, accompanied by a long-lived intermediate that consists of a semiquinone-type radical. Laser excitation of hypericin sodium salt aggregates dispersed in water produces a very short-lived transient, also assigned to a triplet state, which decays, leaving an absorption spectrum, indicating a radical anion species. The latter reacts with oxygen with a rate constant of k ∼ 6 × 10⁷ M^-1 s^-1, suggesting the formation of superoxide.