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Light elements were produced in the first few minutes of the Universe through a sequence of nuclear reactions known as Big Bang nucleosynthesis (BBN).sup.1,2. Among the light elements produced during BBN.sup.1,2, deuterium is an excellent indicator of cosmological parameters because its abundance is highly sensitive to the primordial baryon density and also depends on the number of neutrino species permeating the early Universe. Although astronomical observations of primordial deuterium abundance have reached percent accuracy.sup.3, theoretical predictions.sup.4-6 based on BBN are hampered by large uncertainties on the cross-section of the deuterium burning D(p,[gamma]).sup.3He reaction. Here we show that our improved cross-sections of this reaction lead to BBN estimates of the baryon density at the 1.6 percent level, in excellent agreement with a recent analysis of the cosmic microwave background.sup.7. Improved cross-section data were obtained by exploiting the negligible cosmic-ray background deep underground at the Laboratory for Underground Nuclear Astrophysics (LUNA) of the Laboratori Nazionali del Gran Sasso (Italy).sup.8,9. We bombarded a high-purity deuterium gas target.sup.10 with an intense proton beam from the LUNA 400-kilovolt accelerator.sup.11 and detected the [gamma]-rays from the nuclear reaction under study with a high-purity germanium detector. Our experimental results settle the most uncertain nuclear physics input to BBN calculations and substantially improve the reliability of using primordial abundances to probe the physics of the early Universe. High-precision cross-sections of the nuclear reaction that burns deuterium to create helium-3 are used to produce theoretical estimates of the primordial baryon density that are in agreement with recent astronomical observations., Author(s): V. Mossa [sup.1] , K. Stöckel [sup.2] [sup.3] , F. Cavanna [sup.4] [sup.26] , F. Ferraro [sup.4] [sup.5] , M. Aliotta [sup.6] , F. Barile [sup.1] , D. Bemmerer [...]

A more reliable temperature dependence of the kinetic deuterium isotope effect in a 1,5-hydrogen shift can be obtained by designing the title compound to repress compromising side reactions. The reassessment of the conventional procedure for estimating uncertainties in Arrhenius parameters based on a small number of rate constants has proposed an alternative procedure based on the uncertainties associated with the individual rate constants.

The effects of deuterium labeling on polymer-polymer interactions are readily observable in highly immiscible polymer blends. The deuterium labeling is often used to characterize phenomena such as polymer blending and reactive compatibilization, improved understanding and predictive capabilities into the effects of deuterium labeling are technologically relevant.

A more accurate estimate of the detrapping activation energy [E.sub.A] is provided by careful measurements of the thermally induced detrapping of hydrogen atoms from different octasillsesquioxanes. It is shown that variation of cage substituents has little influence upon [E.sub.A] and radicals or peroxyl groups present in the irradiated specimen do not influence the detrapping process.

Kinetics of thermal equilibrations among monodeuterium labeled 1,3-cycloheptadienes provides activation parameters. This implies a comparatively low E(sub a) barrier balanced by demandingly specific geometric constraints.

Na[([D.sub.x][H.sub.1-x]).sub.3][(Se[O.sub.3]).sub.2] single crystals are grown with a deuterium content and the spectra and relaxation times of the [super 2]H and [super 23]Na nuclei in the mixed Na[([D.sub.0.37][H.sub.0.63]).sub.3][(Se[O.sub.3]).sub.2] crystals are measured as functions of temperature. The effects of partial deuteration of sodium trihydrogen selenite crystals have included not only a shift in the phase transition temperature [T.sub.c] but also a change in the local symmetry.

Several quantum molecular dynamic simulations are conducted to explain the various thermophysical properties of liquid deuterium present under shock compression. The compound is shown to exhibit a local maximum compression ratio of 4.5 at the pressures below 100 GPa, which continuously increases with the pressure.

The article explains the different stages that are observed in the interactions taking place between the deuterium atoms and the amorphous hydrogenated carbon films. Isotope exchange, soft-layer formation and steady-state erosion are shown to be some of the main steps involved in the process.

The temperature dependence of the diffusion coefficients of hydrogen and deuterium in LiH is calculated in terms of a thermodynamical model. The resulting values have agreed well with the experimental data.

A volumetric technique is employed to prepare the temperature-pressure phase diagram of a [D.sub.2]O-[D.sub.2] system at deuterium pressures up to 1.8kbar. The solubility of deuterium in heavy water, hexagonal-ice and the cubic clathrate ice is also studied.

A fast, simple, simple, and general method is described for determining primary kinetic isotope effects (KIEs) on proton transfer in hydroxylic solvents and its application for obtaining primary deuterium isotope effects on protonation of ring-substituted [alpha]-methoxystyrenes X-1 over a broad range of temperature and thermodynamic driving force. The theoretical calculations that reproduce Bronsted parameters and KIEs have to potential to provide a realistic description of the transition state for the proton reactions.

The multi-component molecular orbital-Hartree-Fock (MC_MO-HF) method is used to study the kinetic and geometric isotope effects (KIE and GIE) in the thermal [1,5]-sigmatropic H (or D) shift of (Z)-1,3-pentadiene. It is indicated that the ratio of the rate constant of the reaction for the thermal [1,5]-H and D shifts determined using the MC_MO-HF method is closer to the experimental value.

The feasibility of thermal and catalytic cyclization of 6,6-disubstituted 3,5-dien-1-ynes through a 1,7-hydrogen shift is investigated. The deuterium-labeling experiments have revealed two operable pathways for the metal-catalyzed [1,7]-hydrogen shift of 3,5-dien-1-ynes.

In situ x-ray photoemission spectroscopy is used to study the deuterium and hydrogen oxygen etching effect in nitrogen-implanted iron alloys. A suitable deuterium-nitrogen mixture can increase the surface original steel-hardness up ~40%.

Research is done on thermally driven transport and exchange of hydrogen and deuterium in silicon-based metal-oxide-semiconductor (MOS) device-related structures, which were experimentally, examined using elastic recoil detection analysis. In conclusion, isotope exchange in the polycrystalline Si/SiO2 structure was noticed above 450 degrees C, BPSG revealed very little relative isotope exchange and implications to MOS device processing is examined.