Molecular and cluster structures in 18O

We have studied the multi-nucleon transfer reaction ¹²C ( ⁷Li ,p) at E _lab = 44 MeV, populating states in the oxygen isotope ¹⁸O . The experiments were performed at the Tandem accelerator of the Maier-Leibniz Laboratory in Munich using the high-resolution Q3D magnetic spectrograph. States were populated up to an excitation energy of 21.2MeV with an overall energy resolution of 45keV, and 30 new states of ¹⁸O have been identified. The structure of the rotational bands observed is discussed in terms of cluster bands with the underlying cluster structures: ¹⁴C$ $\displaystyle \otimes$ $\displaystyle \alpha$ $and 12C ? 2n ? $ \alpha$ . Because of the broken intrinsic reflection symmetry in these structures the corresponding rotational bands appear as parity doublets.     

Investigations of EPR g Factors and Rhombic Distortion for the Rhombic Cu2+ Centers in K2Zn1?x Cu x F4 Crystals at Low Temperature

The electron paramagnetic resonance g factors g _i (i?=?x, y, z) of two rhombic Cu²⁺ centers, Cu²⁺(II) and Cu²⁺(III), in K₂Zn_1?x Cu _x F₄ crystals found at low temperature are calculated from the complete diagonalization (of energy matrix) method based on the cluster approach. The calculations show that the ground state wave function of the two rhombically compressed Cu²⁺ centers is $ | {d_{{z^{2} }} }\!\!> $ with a small admixture of $ | {d_{{x^{2} - y^{2} }} } \!\!> $ . The rhombic distortions for both Cu²⁺ centers are obtained from the calculations. The results are discussed.     

Collision-induced dissociation studies on gas-phase titanium oxide cluster cations

Titanium oxide cluster cations $\mathrm{Ti}_{x}\mathrm{O}_{y}^{+}$ are produced in a molecular beam by combining laser ablation of titanium with the supersonic expansion of oxygen into vacuum. The size distribution of the clusters produced is analyzed by time-of-flight reflectron mass spectrometry. The stable clusters appearing in the mass spectrum can be described by the general formula $(\mathrm{TiO})_{m}(\mathrm{TiO}_{2})_{n}(\mathrm{O}_{2})_{k}^{+}$ (with m,n=0,1,2,?? and k=0,1). Additionally, collision-induced dissociation studies of mass selected clusters colliding with Kr atoms in a gas cell have been performed. The results show that the clusters lose neutral O₂, TiO and/or (TiO₂) _n units, and the remaining charged fragments are those with the lowest ionization potentials. From these results the fragmentation cross section of the selected clusters is obtained.     

SIMS of silicon bombarded with Sb m + cluster ions

The emission of Si _n ⁺ (n = 1–11) cluster ions and Si _n X _m ⁺ (X stands for B or Sb) polyatomic ions when bombarding a single silicon crystal with Sb _m ⁺ (m = 1–4) cluster ions with energies E ₀ = 3–12 keV is studied. Considerable nonadditive enhancement of the yield of Si _n ⁺ cluster ions and most polyatomic ions is observed when the number of atoms in the bombarding cluster ions is increased. The sensitivity enhancement factor for detecting boron impurities is as high as 50 when the cluster-SIMS-molecule technique is applied.     

High-spin excitations of the odd-odd 88 37Rb51 and 86 35Br51 nuclei: \pip3/2 \nud5/2 and \pif5/2 \nud5/2 residual interactions

The odd-odd ⁸⁸ ₃₇Rb₅₁ and ⁸⁶ ₃₅Br₅₁ nuclei have been produced as fission fragments in the fusion reaction ¹⁸O$ + $²⁰⁸Pb at 85MeV bombarding energy and studied with the Euroball IV array. Their high-spin level schemes have been built from the triple $ \gamma$ -ray coincidence data and $ \gamma$ - $ \gamma$ angular correlations have been analyzed in order to assign spin and parity values to many observed states. The proposed configurations involve proton excitations from three sub-shells located close to the Fermi levels, $ \pi$ p _3/2 , $ \pi$ f _5/2 , and $ \pi$ g _9/2 , the $ \nu$ d _5/2 neutron acting as a spectator. The residual $ \pi$ $ \nu$ interactions are extracted from the multiplets of states resulting from the $ \pi$ p _3/2 $ \nu$ d _5/2 and $ \pi$ f _5/2 $ \nu$ d _5/2 configurations. The empirical values of the latter are discussed and compared to those known in two similar configurations having j _p = j _n with l _p = l _n + 1 , where the role of the tensor force had been highlighted.     

Baryon resonances as hadronic molecule states with kaons

We investigate hadronic molecule states of $K \bar K N$ and $\bar K \bar K N$ systems with I?=?1/2 and J ^P ?=?1/2^?+?, assuming that Λ(1405) and the scalar mesons, f ₀(980), a ₀(980), are reproduced as quasi-bound states of $\bar KN$ and $K \bar K$ . Performing non-relativistic three-body calculations for these systems, we find weakly bound states for $K \bar K N$ and $\bar K \bar K N$ around 1900 MeV, which correspond to new baryon resonances of N ^* and Ξ ^* with J ^P ?=?1/2^?+?. We find that these resonances have cluster structure of the two-body bound state keeping its properties as in the isolated two-particle system.     

Radiative open charm decay of the Y(3940) , Z(3930) , X(4160) resonances

We determine the radiative decay amplitudes for the decay into D^* and $ \bar{{D}}$ $ \gamma$ , or D ^* _s and $ \bar{{D}}_{s}^{}$ $ \gamma$ of some of the charmonium-like states classified as X , Y , Z resonances, plus some other hidden charm states which are dynamically generated from the interaction of vector mesons with charm. The mass distributions as a function of the $ \bar{{D}}$ $ \gamma$ or $ \bar{{D}}_{s}^{}$ $ \gamma$ invariant mass show a peculiar behavior as a consequence of the D ^* $ \bar{{D}}^{*}_{}$ nature of these states. The experimental search of these magnitudes can shed light on the nature of these states.     

Electrochemical behavior and DNA-binding properties of binuclear copper(II) complex containing mixed ligands of N-hydroxyethylaminoethyl oxamido and 2,2′-bipyridine

The electrochemical property of dinuclear copper(II) complex containing mixed ligands of N-hydroxyethylaminoethyl oxamido and 2,2′-bipyridine [Cu₂(bpy)₂(HAO) ₂ ²⁺ ] was studied with cyclic voltammetry. Cu₂(bpy)₂(HAO) ₂ ²⁺ had irreversible oxidation peaks in 0.1 mol/L NaCl solution at the stearic acid-modified carbon paste electrode. Cyclic voltammetry and absorption spectra measurements were used to study the interaction between Cu₂(bpy)₂(HAO) ₂ ²⁺ and herring fish sperm DNA. All the experimental results showed that Cu₂(bpy)₂(HAO) ₂ ²⁺ interacted with DNA mainly through electrostatic affinity to make tiny difference between Cu₂(bpy)₂(HAO) ₂ ²⁺ –ssDNA and Cu₂(bpy)₂(HAO) ₂ ²⁺ –dsDNA. The binding ratio and the binding constant of DNA–Cu₂(bpy)₂(HAO) ₂ ²⁺ were calculated as 1:1 and 6.41?×?10⁴, respectively. The redox peak current of Cu₂(bpy)₂(HAO) ₂ ²⁺ decreased markedly after its interaction with DNA. This was used to detect the concentration of DNA quantitatively.     

2α + t Cluster Structure in 11B

Structures of excited states in ¹¹B are investigated with a method of β – γ constraint antisymmetrized molecular dynamics in combination with the generator coordinate method. Various cluster structures are suggested in excited states. For negative-parity states, we suggest a band with a 2α + t cluster structure. This band starts from the ${3/2^{-}_{3}}$ state and can correspond to the experimental band observed recently. We find that the feature of the ${3/2^{-}_{3}}$ is quite similar to the ${0^{+}_{2}}$ state in ¹²C.     

Confrontation between the quasiparticle-phonon nuclear model and the interacting boson model for deformed nuclei

TheK ^π=0⁺, 2⁺ and 4⁺ states are considered in doubly even deformed nuclei. It is shown that in the quasiparticle-phonon nuclear model (QPNM) and in the interacting boson model (IBM) a vibrational state has one dominating component. The states withK _n ^π =0 ₃ ⁺ , 0 ₄ ⁺ 0 ₅ ⁺ 2 ₂ ⁺ , 2 ₃ ⁺ , 4 ₁ ⁺ and 4 ₂ ⁺ have a dominating one-phonon component within the QPNM and a two- or three-boson component within the IBM. According to the QPNM the contribution of two-phonon components to the wave functions of these states is less than 10%, i.e. there is a qualitative discrepancy in describing the structure of these states within the QPNM and the IBM. The experimental data indicate the existence in these states of one-phonon or two-quasiparticle components. They are rather well described within the QPNM. These states cannot be described within the IBM. This is due to the fact that the IBM takes into account only a small part of the space of two-quasiparticle states, just the one entering intoΒ- andγ-vibrational states.     

Optically induced structural transformation in disordered kesterite Cu2ZnSnS4

The kesterite-structured semiconductor Cu₂ZnSnS₄ is one of the most promising compound for earth-abundant low-cost solar cells. One of the complex problem on this way deals with its stoichiometry. In this work Raman spectra of Cu-rich Cu₂ZnSnS₄ crystals are discussed in connection with the non-stoichiometric composition and disordering within the cation sublattice of the kesterite. The shift of the main A-peak from 338 to 331 cm^?1 and its broadening are attributed here to transition from the kesterite (I $\bar 4$ symmetry) to the disordered kesterite structure (I $\bar 4$ 2m symmetry). It is shown that this transition may also be driven by an intense light, which could stimulate transformation of Cu⁺-ion to Cu²⁺-ions and facilitates generation of Cu_Zn-defects on 2d-crystalographic positions.     

Charged particle and π0 multiplicity distributions and the annihilation properties of\bar p p interactions at 70 GeV/c

The elastic and inelastic \(\bar p\) p cross sections at 70 GeV/c have been determined in an experiment performed at CERN using BEBC equipped with a TST. The topological cross sections were measured and the moments of the inelastic multiplicity distribution are 〈n _c 〉=6.16±0.09, 〈n _c 〉/D=2.04±0.05 andf ₂ ^cc =2.97±0.03. The average number of Dalitz pairs per inelastic event is (3.12±0.09)×10^?2. Assuming that these all arise from π⁰ decay the average π⁰ multiplicity is \(\langle n_{\pi ^0 } \rangle = 2.71 \pm 0.14\) . The \(\bar p\) p?pp cross section differences lead to an annihilation cross section σ _A = 4.42±0.41 mb and the moments of the annihilation multiplicty distribution are 〈n _A 〉=8.0±0.3, 〈n _A 〉/D=2.5±0.2 andf ₂ ^A?? =?1.4±0.3. An independent check of σ _A was made by investigating fast forward charged and neutral secondary interactions in the TST and in the surrounding neon-hydrogen mixture, and gives a value σ _A = 5.0±1.6 mb. The ratio of fast \(\bar n\) to \(\bar p\) production in non-annihilation interactions at 70 GeV/c is found to be 0.45±0.11.     

Neutral-charged particle correlations in proton-proton collisions in the framework of a two-component model

The data on \(\bar N_0 \left( {n\_} \right)\) , the average number of neutrals as a function ofn _?, the number of negatively charged particles produced, is fitted at 69, 205 and 303 GeV/c. The two-component model used for the charged multiplicity distributionP _n, is one which envisages two distinct types of collisions and is the simplest such model consistent with charge conservation. We find that the data on \(\bar N_0 \left( {n\_} \right)\) can be fitted reasonably well. Further, our results, based on this model forP _n, suggest that at 50 GeV/c, \(\bar N_0 \left( {n\_} \right)\) should increase linearly withn _?and that neutral-negative correlations should be present in the central component.     

Demonstration of the origins of cooperativity within SU2×L 6 mapping over\left\{ {I\tilde H_\upsilon } \right\} Liouvillian carrier subspaces characterising the MQ-NMR cluster [A]6(L 6) and its\{ |kq\upsilon :[\tilde \lambda ] > > \} tensorial bases

The fundamental mappings over carrier subspace and substructures associated with \(\{ |kq\upsilon > > \} \) augmented spin algebras of Liouville space, and their mapping onto a subduced symmetry, are derived for [A]₆(L ₆) spin clusters within the combinatorial context of Rota-Cayley algebra over a field. Use of suitable lexical sets of combinatorialp-tuples (number partitions) over {|IM(M ₁?M _n )>}M, followed by the subsequent use ofL _n inner tensor product (ITP) algebra, allows the substructure of Liouville space to be derived. For SU2×L ₆ mapping over the simply-reducible \(\left\{ {I\tilde H_\upsilon } \right\}\) carrier subspaces, the \(D^k \left( {\tilde U} \right) \times \tilde \Gamma ^{\left[ {\tilde \lambda } \right]} \left( \upsilon \right)\) (L ₆) dual irreps, also arise as a consequence of the Liouville space recoupling termsv≡{k ₁?k _n } being distinct labels for \(\left\{ {I\tilde H_\upsilon } \right\}\) which are themselves amenible to combinatorial analysis within the concept of Rota-Cayley algebra. Hence, theL _n -induced symmetry aspects of multiquantum NMR density matrix formalisms and their dual \(\{ |kq\upsilon :[\tilde \lambda ] > > \} \) tensorial bases of spin cluster problems are derived and the nature of the cooperative, aspect between the individual symmetries comprising the duality is demonstrated, i.e. in the context of the operator bases of Liouville space. These practical arguments correlate, well with those based on an augmented boson pattern algebra derived from a Heisenburg algebra for superoperators, ?_±,?₀. An earlier, treatment of conventional Hilbert space SU2×L ₆ dualitycould only be realised in terms of standard SU2 boson algebra. Since the recoupling Rota-‘field’v for Liouville space is an explicit aspect of the dual mapping, a direct demonstration of cooperativity exists.     

Peculiarities of the electronic structure of Yb, In, Ag, and Cu in the heavy-fermion system YbIn1−x AgxCu4

The method of x-ray spectral line displacement is used for studying the electronic structure, i.e., the population of the 4f shell of Yb, 5s shells of In and Ag, and 4s shell of Cu, in the YbIn_1?x Ag_xCu₄ heavy-fermion system (0≤x≤1, T=300 K; T=77, 300, and 1000 K for YbIn_0.7Ag_0.3Cu₄). It is shown that Yb is in a state with fractional valence whose value is independent of x (or on the type of the partner, i.e., In and Ag) in the entire range of compositions and is equal to $\bar m = 2.91 \pm 0.01$ at T=300 K. An increase in the population of the In s states of In, Ag, and Cu (as compared to metals) is observed: $\overline {\Delta n_s } (In) = 0.65 \pm 0.05 el/at$ , $\overline {\Delta n_s } (Ag) = 0.71 \pm 0.09 el/at$ , and $\overline {\Delta n_s } (Cu) = 0.08 \pm 0.02 el/at$ . A practically linear decrease in the valence of Yb to the value m(T=1000 K)=2.81±0.02 is observed in YbIn_0.7Ag_0.3Cu₄ upon an increase in temperature from T=77 to 1000 K.     

Gas-Like Cluster States in Finite Nuclei

Gas-like α cluster states are investigated in ¹⁶O with the use of 4α OCM (orthogonality condition model) and GEM (Gauss expansion method). α-particle condensed state is found slightly above the 4α threshold as the ${0_6^+}$ state. The candidates of the ${\alpha + {^{12}{\rm C}(0_2^+)}}$ rotational states are also found at a few megaelectron volt above the condensate. The ${0_6^+}$ state is shown to have an analogue structure to the Hoyle state ${({^{12}{\rm C}}(0_2^+))}$ and its relation with the α+ Hoyle-like rotational states is also discussed.     

g-factors of the ground state rotational band of158Dy

Theg-factors of the four lowest states of the ground state rotational band of¹⁵⁸Dy have been determined asg(2 ₁ ⁺ )=+0.362(23),g(4 ₁ ^su+ )=+0.340(20),g(6 ₁ ^su+ )=+0.207(36) andg(8 ₁ ^su+ )=+0.21(11). Theg-factors of the 2⁺ and 4⁺ states were measured by the IPAC method with radioactive samples of 2.4 h¹⁵⁸Er in external magnetic fields. To investigate the higher states, for the first time an on-line γ—γ IPAC experiment was performed with the reaction¹⁵⁶Gd(α, 2n)¹⁵⁸Dy by use of the static hyperfine field of DyGd.     

Strong magnetic fields,Dirichlet boundaries,and spectral gaps

We consider magnetic Schrödinger operators $$H(\lambda \vec a) = ( - i\nabla - \lambda \vec a(x))^2$$ inL ₂(R ⁿ ), where $\vec a \in C^1 (R^n ;R^n )$ and λεR. LettingM={x;B(x)=0}, whereB is the magnetic field associated with $\vec a$ , and $M_{\vec a} = \{ x;\vec a(x) = 0\}$ , we prove that $H(\lambda \vec a)$ converges to the (Dirichlet) Laplacian on the closed setM in the strong resolvent sense, as λ→∞,provided the set $M\backslash M_{\vec a}$ has measure zero. In various situations, which include the case of periodic fields, we even obtain norm resolvent convergence (again under the condition that $M\backslash M_{\vec a}$ has measure zero). As a consequence, if we are given a periodic fieldB where the regions withB=0 have non-empty interior and are enclosed by the region withB≠0, magnetic wells will be created when λ is large, opening up gaps in the spectrum of $H(\lambda \vec a)$ . We finally address the question of absolute continuity of $\vec a$ for periodic $H(\vec a)$ .