Helium-helium clustering states inBe12

Abstract

An inelastic excitation experiment was performed with a 12 Be beam at 29 MeV/u on a carbon target. New resonances close to the respective cluster separation thresholds were observed in 12 Be for the 4 He + 8 He and 6 He + 6 He decay channels, confirming the previously proposed molecular rotational bands. Using the model-independent angular correlation analysis, a 0 + spin parity is assigned to the remarkably large peak at 10.3 MeV in the 4 He + 8 He channel. A distorted wave Born approximation (DWBA) calculation was compared to the experimental differential cross section of this state, resulting in a largely enhanced monopole transition matrix element of 7.0 ± 1.0 fm 2 , in good agreement with the generalized two-center cluster model (GTCM) prediction assuming a preformed α-4n-α configuration. Together with the previously reported large cluster spectroscopic factor, the strong clustering in 12 Be is well demonstrated. The detection focused on the most forward angles, by using a zero-deg telescope, is essential in the present measurement.

Chiral and helical p -wave superconductivity in doped bilayer BiH

“…The obtained pairing function is similar to that in Ref. 10 where the Fermi level is far below the vHS, suggesting the robustness of this type of pairing symmetry. Indeed, similar results are obtained for n = 0.61, corresponding to the top line in Fig.1(a), with U = 1.6 eV, J H = 0.4U and V = 0, although the Fermi level is slightly above the vHS and the Fermi pockets now concentrate on the M points, see the inset in Fig.3(b).…”

“…According to first principle calculation, 8-10 the band electrons near the Fermi level are mainly derived from the x-and y-orbitals of Bi. A corresponding tight-binding model can be written as [8][9][10]18 ,…”

“…Hatree-Fock mean field theory shows that triplet pairing could be stabilized even by small electron doping of the insulating compound, with a small electron pocket around the zone center and a Fermi level relatively far from the type-II vHS. 10 However, the mean field coupling constant is about λ ∼ 10 −2 , implying a tiny transition temperature according to T c ∝ e −1/λ . This motivates us to consider filling levels near the type-II vHS (realizable by higher electron doping).…”

Aqueous Spray Pyrolysis of Cu2O Films: Influence of Reducing Agent and Acetic Acid Addition

“…The two peaks at 2360 and 2340 cm À 1 , seen in all three spectra, are characteristic for physisorbed CO 2 [67] that is either present as decomposition product of the solution components during the spraying process, or arising from adsorbed CO 2 on the sample's surface, as it is exposed to the air. Since this peak is not present for the pure glass substrate, it is concluded that the presence of CO 2 arises from the spraying process.…”

Investigation of the near-threshold cluster resonance in 14 C

“…The relative energy (E rel ) of the decay fragments 10 Be + α can be calculated from their kinetic energies (T a , T b ) and the opening angle θ, according to the invariant mass (IM) method [24], which takes part in the excitation energy E x :…”