Magnetic interactions in thiazyl-based magnets: The role of the charge and spin densities

The crystal structure of the organic radical p-O2NC6F4CNSSN was determined at 20 K through a single-crystal neutron-diffraction experiment. It crystallises in the tetragonal space group P41212, unchanged from a previous single-crystal X-ray diffraction experiment at 220 K although there are some changes in molecular geometry and intermolecular contacts arising from the contraction of the unit cell. Polarized neutron diffraction at 1.5 K revealed that the spin distribution is predominantly localised on the N and S atoms of the heterocyclic ring with a small negative spin density on the heterocyclic C atom. Spin populations determined using a multipolar analysis were -0.06, +0.25 and +0.28 on the C, N and S sites, respectively. These spin populations are in excellent agreement with both ab-initio DFT calculations (spin populations on the C, N and S sites of -0.07, 0.22 and 0.31, respectively) and cw-EPR studies which estimated the spin population on the N site as 0.24. The DFT calculated spin density revealed less than 1% spin delocalisation onto the perfluoroaryl ring, several orders of magnitude lower than the density on the heterocyclic ring. cw-ENDOR studies at both X-band (9 GHz) and Q-band (34 GHz) frequencies probed the spin populations at the two chemically distinct F atoms. These spin populations on the F atoms ortho and meta to the dithiadiazolyl ring are of magnitude 10-3 and 10-4 respectively. Additional high-resolution single-crystal X-ray diffraction studies at 100 K analysed within the atoms-in-molecules (AIM) framework gave detailed information on the charge density distributio

Spin Chirality in a Molecular Dysprosium Triangle: the Archetype of the Non-Collinear Ising Model

Single crystal magnetic studies combined with a theoretical analysis show that cancellation of the magnetic moments in the trinuclear Dy3+ cluster [Dy3(OH)2L3Cl(H2O)5]Cl3, resulting in a non-magnetic ground doublet, originates from the non-collinearity of the single ion easy axes of magnetization of the Dy3+ ions that lie in the plane of the triangle at 120 (deg.) one from each other. This gives rise to a peculiar chiral nature of the ground non-magnetic doublet and to slow relaxation of the magnetization with abrupt accelerations at the crossings of the discrete energy levels.Comment: 4 pages and 5 figure

Applying emerging 3D visualization technologies to macro and micro anatomical datasets, for the improvement of operative planning, performance and outcomes in colon cancer surgery

Right colectomy with extended D3 mesenterectomy is an advanced surgical technique aiming for the curative treatment of right-sided colon cancer by removing mesenteric tissue around the superior mesenteric vessels. The main aim of this dissertation was to test and validate different 3D visualization formats of the central mesenteric vasculature for the surgeon to apply, pre- and intraoperatively, as a navigation map during colon cancer surgery. The specific aims of the thesis were to find out if 3D printed vascular models are accurate enough to mirror the real linear dimensions of vascular structures; to identify if semi-automated (rapid) methods for creating vascular structures in 3D are accurate enough for clinical use; to test an in-house navigation system for open surgery using holographic imaging (virtual 3D images) and Mixed-Reality technology; and to describe the topography of the superior mesenteric nerve plexus using three different methodological approaches, as well as to assess the degree of nerve plexus injury after performing such advanced surgical resections

Monarchia, nazione e nazionalismo in Europa (1830-1914)

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Memoria e Ricerca sur Monarchia, nazione e nazionalismo in Europa (1830-1914)

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La monarchia e la nazionalizzazione degli Italiani (1861-1900)

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Introduction

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Introduction

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