arXiv subjects

T. Dossing

Publications and source records attributed to T. Dossing.

4 recordsLinked to original sources

arXiv2010

Linear response of light deformed nuclei investigated by self-consistent quasiparticle random-phase-approximation

We present a calculation of the properties of vibrational states in deformed, axially--symmetric even--even nuclei, within the framework of a fully self--consistent Quasparticle Random Phase Approximation (QRPA). The same Skyrme energy density and density-dependent pairing functionals are used to calculate the mean field and the residual interaction in the particle-hole and particle-particle channels. We have tested our software in the case of spherical nuclei against fully self consistent calculations published in the literature, finding excellent agreement. We investigate the consequences of neglecting the spin-orbit and Coulomb residual interactions in QRPA. Furthermore we discuss the improvement obtained in the QRPA result associated with the removal of spurious modes. Isoscalar and isovector responses in the deformed ${}^{24-26}$Mg, $^{34}$Mg isotopes are presented and compared to experimental findings.

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arXiv2004

Violation and persistence of the K-quantum number in warm rotating nuclei

The validity of the K-quantum number in rapidly rotating warm nuclei is investigated as a function of thermal excitation energy U and angular momentum I, for the rare-earth nucleus 163Er. The quantal eigenstates are described with a shell model which combines a cranked Nilsson mean-field and a residual two-body interaction, together with a term which takes into account the angular momentum carried by the K-quantum number in an approximate way. K-mixing is produced by the interplay of the Coriolis interaction and the residual interaction; it is weak in the region of the discrete rotational bands (U \lesim 1MeV), but it gradually increases until the limit of complete violation of the K-quantum number is approached around U \sim 2 - 2.5 MeV. The calculated matrix elements between bands having different K-quantum numbers decrease exponentially as a function of $ΔK$, in qualitative agreement with recent data.

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arXiv2002

Rotational Damping and Compound Formation in Warm Rotating Nuclei

The rotational damping width Γ_{rot} and the compound damping width Γ_{comp} are two fundamental quantities that characterize rapidly rotating compound nuclei having finite thermal excitation energy. A two-component structure in the strength function of consecutive E2 transitions reflects the two widths, and it causes characteristic features in the double and triple gamma-ray spectra. We discuss a new method to extract experimentally values of Γ_{rot} and Γ_{comp}. The first preliminary result of this method is presented.

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arXiv2001

Gamma-ray strength functions in thermally excited rotating nuclei

A general discussion and illustration is given of strength functions for rotational transitions in two-dimensional E(gamma_1) x E(gamma_2) spectra. Especially, a narrow component should be proportional to the compound damping width, related to the mixing of basis rotational bands into compound bands with fragmented transition strength. Three E(gamma_1) x E(gamma_2) spectra are made by setting gates on triple coincidences, selecting cascades which feed into specific low-lying bands in the nucleus 168Hf. In each of the gated spectra, we find a ridge, carrying about 100 decay paths. This ridge is ascribed to rotational transitions in the excitation energy range of 1.0 to 1.5 MeV above the yrast line. The FWHM of the ridges are around 40 keV, about a factor of two smaller than calculated on the basis of mixed cranked mean field bands.

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