New precision measurements of dµd fusion

A new experiment was started at PSI aiming for high-precision and complete studies of dµd fusion in D₂, HD and D₂/H₂ gas mixtures. A high-pressure ionization chamber surrounded by a set of neutron counters is used to observe dd-fusion at temperatures between 25 and 350 K. Here we report preliminary results from the first test run with pure D₂ filling.     

Three-body break-up in the d + d → d + p + n reaction

Neutron-charged-particle and charged-particle-charged-particle coincidence spectra from the d + d → d + p + n reaction were measured for θ₁ = −θ₂ = 20° at bombarding energies 6–13 MeV. Deuteron-neutron and deuteron-proton spectra for θ₁ = −θ₂ are dominated by a broad peak associated with deuteron-nucleon quasi-free scattering. The measured data were interpreted using the quasi-free scattering model. The constructed model describes the general behavior of the coincidence spectra rather well, although the calculated spectral shapes are broader than the measured ones. The limitations of the simple quasi-free scattering model are shown also by the fact that the model predicts an order of magnitude too high cross section and that the normalization constant to the measured peak cross section is energy dependent.     

O(d,d) symmetry in quantum cosmology

We analyze the quantum cosmology of one-loop string effective models which exhibit an O(d, d) symmetry. It is shown that due to the large symmetry of these models the Wheeler-de Witt equation can completely be solved. As a result, we find a basis of solutions with well-defined transformation properties under O(d, d) and under scale factor duality in particular. The general results are explicitly applied to 2-dimensional target spaces while some aspects of higher dimensional cases are also discussed. Moreover, a semiclassical wave function for the 2-dimensional black hole is constructed as a superposition of our basis.     

Topologically Stable Lumps in SO(d) Gauged O((d+1) Sigma Models in d Dimensions: d =2,3,4

The gauge-invariant topological charge is defined for, and the inequalities supplying the lower bound on the action of an SO(4) gauged O(5) sigma model in four dimensions are established. The consistency of the solution with finiteness of the action and with topological stability is briefly verified for a particular dynamical example. Against the background of the topologically stable finite energy solitons of SO(d) gauged O(d+1) sigma models in d dimensions already known for d=2 and for d=3, the present example can be viewed as a demonstration by induction for the existence of such solitons in the case of arbitrary k.     

Mechanism of reactions induced by 7 MeV deuterons on9Be [(d,p), (d,d), (d,t), (d,4He)]

Angular distributions of protons, deuterons, tritons and alpha-particles emitted from the reactions in thed+⁹Be-system atE _d =7 MeV as well as excitation functions at selected angles in the energy rangeE _d =6.5–7.5 MeV (LAB) were measured. The potential part of the elastic scattering is described by the phenomenological optical model. The compound nucleus contribution to all exit channels is determined using the Hauser-Feshbach model. The collective excitation of the 2.43 MeV excited state of⁹Be and transfer processes are analysed within the DWBA formalism. The analyses suggest a significant contribution of five-nucleon transfer to the (d,⁴He) channel.     

Density-functional investigation of 3d,4d,5d impurity doped Au6 clusters

The general features of the geometries and electronic properties for 3d,4d,and 5d transition-metal atom doped Au 6 clusters are systematically investigated by using relativistic all-electron density functional theory in the generalized gradient approximation(GGA).A number of structural isomers are considered to search the lowest-energy structures of M@Au 6 clusters(M=3d,4d and 5d transition-metal atoms),and the transition metal atom locating in the centre of an Au 6 ring is found to be in the ground state for all the M@Au 6 clusters.All doped clusters,expect for Pd@Au 6,show large relative binding energies compared with a pure Au 7 cluster,indicating that doping by 3d,4d,5d transition-metal atoms could stabilize the Au 6 ring and promote the formation of a new binary alloy cluster.     

The Estimation of the Difference Between d(d,n)3He and d(d,p)T Cross Sections in the Cold Fusion

The difference between two reaction cross sections of d(d, p)T and d(d, n)³He has been estimated in the cold fusion. It is caused by the different potential wall transmission and the angular distribution due to the structure.of deuterons. The rough estimation indicates that the branching ratio b about two orders of magnitude.     

Experimental transition probabilities for lines arising from the 4d5p and 4d5d configurations of ZrIII

Relative transition probabilities for 120 lines arising from the 4d5p and 4d5d configurations of ZrIII were determined from measurements of emission-line intensities in a laser-produced plasma. The experiment was carried out with Cu-Zr alloy with a Zr content lower than 13% in order to have an optically thin plasma. Transition probabilities were placed on an absolute scale by using theoretical lifetimes, line-strength sum rules and Boltzmann plot. Comparison of the present experimental results with the available theoretical data is made.     

Heats of formation of 3d and 4d transition metal hydrides

One electron energy spectra are used to explain the heats of formation of stoichiometric transition metal hydrides across the 3d and 4d rows. The trends agree reasonably with existing experimental information. The magnitudes are predominantly (but not exclusively) determined by the formation of a metal-H bonding band. In contrast to the screened proton model, the result is not directly related to the Fermi level density of states.     

The (τ,d), (d,p) and (d,n) reactions on28Si

The model of a three-particle proton cluster coupled to the quadrupole vibrational field is applied to¹²⁹I. The energy spectrum and spectroscopic factors, as obtained in a (³He,d) stripping reaction, are calculated and compared with experimental data. With the wave functions obtained magnetic-dipole and electric-quadrupole moments are derived.     

Nondynamical calculation of polarization observables in d+d reactions at low energies

The parametrization of polarization observables in terms of (l, s, J) matrix elements is given for²H(d, p)³H and²H(d, n)³He reactions at low energies. It is shown that transverse polarizations of outgoing nucleons are to be measured in order to obtain a complete set of cross-section, analysing powers, spin-correlation and polarization transfer experiments.     

光折变材料Cu∶KNSBN的晶格振动和d－d电子跃迁

比较了铜掺杂钾钠铌酸锶钡（Ｃｕ∶ＫＮＳＢＮ）和钾钠铌酸锶钡（ＫＮＳＢＮ）两样品的晶格振动和ｄ－ｄ电子跃迁谱，对于拉曼（Ｒａｍａｎ）谱，Ａ１（ｚ）对称类的差别较小，Ｅ（ｘｙ）对称类的差别最大；对于红外反射谱，两对称类的均差别较大，认为Ｃｕ２＋部分填充了晶格Ａ位和Ｃ位，可见光范围内，ｄ－ｄ电子跃迁谱表明Ｃｕ２＋在晶体中形成两个深能级２．５０ｅＶ和２．６４ｅＶ。