A5023217075- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- X-ray Diffraction in Crystallography
- Crystal Structures and Properties
- Crystallization and Solubility Studies
- Crystallography and molecular interactions
- Mineralogy and Gemology Studies
- Nuclear physics research studies
- Dark Matter and Cosmic Phenomena
- Geological and Geochemical Analysis
- History and advancements in chemistry
- High-pressure geophysics and materials
- Particle Detector Development and Performance
- Clay minerals and soil interactions
- Solid-state spectroscopy and crystallography
- Cosmology and Gravitation Theories
- Inorganic Fluorides and Related Compounds
- Molecular spectroscopy and chirality
- Quasicrystal Structures and Properties
- Atomic and Molecular Physics
- Various Chemistry Research Topics
- Astronomical and nuclear sciences
- Force Microscopy Techniques and Applications
- Neutrino Physics Research
Université de Lorraine
2015-2024
Centre National de la Recherche Scientifique
2014-2024
Laboratoire de Cristallographie, Résonance Magnétique et Modélisations
2015-2024
Kyoto University
2015-2016
Istituto Nazionale di Fisica Nucleare, Sezione di Padova
2005-2015
Tokyo Institute of Technology
2015
European Organization for Nuclear Research
2012-2013
Institute of High Energy Physics
2010-2012
Istituto Nazionale di Fisica Nucleare, Sezione di Pavia
2012
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro
2005-2011
The charge distribution method describes non-molecular crystal structures in a Madelung-type approach which the formal oxidation number (`charge') of each atom is distributed among its neighbours. sum charges gives back input when structure correctly refined and well balanced, so that can be used for validation analysis over- underbonding effects. A new version software to compute presented, now with CIF parser graphical user interface.
Multinucleon transfer reactions in $^{40}\mathrm{Ca}+^{96}\mathrm{Zr}$ and $^{90}\mathrm{Zr}+^{208}\mathrm{Pb}$ have been measured at energies close to the Coulomb barrier a high-resolution \ensuremath{\gamma}-particle coincidence experiment. The large-solid-angle magnetic spectrometer PRISMA coupled CLARA \ensuremath{\gamma} array has employed. Trajectory reconstruction applied for complete identification of products. Mass charge yields, total kinetic energy losses, transitions binary...
Space groups are classified, according to different criteria, into types, classes, systems and families. Depending on the specific research topic, some of these concepts will be more relevant everyday crystallographer than others. Unfortunately, incorrect use classification terms often leads misunderstandings. This article presents rationale behind levels.
A new route to apply the charge distribution (CHARDI) method structures based on heteroligand coordination polyhedra is presented. The previous algorithm used scale factors computed in an iterative way assumption (which turned out be not always correct) that a real over–under bonding effect affects mainly anionic charges of each single anion, without grossly modifying total type anion. new, more general approach any priori but treats separately homoligand sub-polyhedra and attributes atom...
Through the years, mineralogical studies have produced a tremendous amount of data on atomic arrangement and mineral properties. Quite often, structural analysis has led to elucidate role played by minor components, giving interesting insights into physico-chemical conditions crystallization allowing description unpredictable structures that represented body knowledge critical for assessing their technological potentialities. Using such rich database, containing many basic acquisitions,...
It is shown that one of the main reasons for most failures methods calculating distance-dependent bond strengths related to distortion coordination polyhedra. The charge distribution (CD) method which depends on only universal empirical parameter (contraction parameter) modified include: (i) an iterative calculation effective number (ECoN), deal with structures containing very distorted polyhedra; (ii) a specific contraction treat any type hydrogen bond; (iii) scale factors subshells,...
The charge distribution (CD) method, previously introduced as a development of the bond-valence (BV) approach, is applied for first time to mineral structures, and specifically pyroxenes. CD essentially involves Effective Coordination Number (ECoN) cation among all neighboring anions. This then interpreted in terms 'charges', where 'charge' represents formal oxidation state. Differently from BV, description depends upon geometry each coordination polyhedron, which characterized through ECoN...
A classification scheme relating the chirality of molecules to type crystal structures (chiral or achiral) they may form is presented. With respect similar classifications proposed in past, some corrections and extensions are introduced. In particular, (1) it shown that chiral from achiral can occur 28 types space group having screw axes n p , with ≠ /2, not any Sohncke group; (2) restriction on Z ′ > 1 for kryptoracemates contradicted by examples = 1; (3) case scalemic enantioenriched...
Using a method whereby molecular and atomic ions are independently selected, an isobarically pure beam of $^{70}\mathrm{Se}$ was postaccelerated to energy 206 MeV using REX-ISOLDE. Coulomb-excitation yields for states in the target nuclei were deduced by recording deexcitation $\ensuremath{\gamma}$ rays highly segmented MINIBALL $\ensuremath{\gamma}$-ray spectrometer coincidence with scattered particles silicon detector. At these energies, yield first ${2}^{+}$ state is expected be strongly...
A critical analysis of some basic notions often overlooked in crystallographic education is presented to correct common oversights occurring both the literature and textbooks. The crystal forms (face forms), defined terms their geometric eigensymmetry, are 47 number, not 48 as found literature. split dihedron into dome sphenoid calls for consideration physical properties faces building a form; that case, however, same criterion should be used all forms. By taking handedness representative...
Twinning by merohedry involves crystals whose point group is a subgroup of the lattice symmetry. The case with metric symmetry higher than syngony, not considered in previous classifications twinning, here analysed terms group-subgroup relations and pseudo-symmetry. Merohedry classified into syngonic merohedry, depending on whether crystal equal to or syngony. It shown that corresponds degeneration pseudo-merohedry zero obliquity, reticular twin index 1. A revised classification three...
Following the heavy-ion fusion-evaporation reaction $^{32}\mathrm{S}+^{24}\mathrm{M}\mathrm{g}$ at 95 MeV beam energy lifetimes of analogue states in ${T}_{z}=\ifmmode\pm\else\textpm\fi{}1/2$ $A=51$ mirror nuclei $^{51}\mathrm{F}\mathrm{e}$ and $^{51}\mathrm{M}\mathrm{n}$ have been measured using Cologne plunger device coupled to GASP $\ensuremath{\gamma}$-ray spectrometer. The deduced $B(E2;27/{2}^{\ensuremath{-}}\ensuremath{\rightarrow}23/{2}^{\ensuremath{-}})$ values afford a unique...
Excited states up to Iπ=8+ in the neutron-rich nucleus 58Cr have been identified by using a new experimental setup composed of large acceptance magnetic spectrometer PRISMA and highly efficient γ-detector array CLARA. Interestingly, excitation energy sequence ground-state band follows one expected E(5) dynamical symmetry for at critical point shape phase transition from spherical vibrator (U(5)) γ-soft rotor (O(6)). For first time, same physical system, scale shell-model calculations full fp...
The charge distribution (CHARDI) method is a self-consistent generalization of Pauling's concept bond strength which does not make use empirical parameters but exploits the experimental geometry coordination polyhedra building crystal structure. In two previous articles this series [Nespolo et al. (1999). Acta Cryst. B55, 902-916; Nespolo (2001). B57, 652-664], we have presented features and advantages approach its extension to distorted heterovalent hydrogen bonds. third article generalize...
Abstract The geometric theory of twinning was developed almost a century ago. Despite its age, it still represents the fundamental approach to analysis and interpretation twinned crystals, in both direct reciprocal space. In recent years, this has been extended not only formalism (group-subgroup analysis, chromatic symmetry) but also classification special cases that were recognized before. geometrical is thus reviewed here with emphasis on lattice aspects developments. various types twins...
A series of guidelines (tips) to provide a satisfactory characterization twinned sample is provided, and traps avoid pointed out. The fundamental concepts definitions are summarized, which represent the minimal theoretical background behind these guidelines.
Volume A of International Tables for Crystallography is the reference space-group information. However, content not exhaustive because many space groups a variety settings may be chosen but all them are described in detail or even fully listed. The use alternative seem an unnecessary complication when purpose just to describe crystal structure; however, these utmost importance number tasks, such as investigation structure relations between polymorphs derivative structures, study...
In this article, several mistakes occurring in the description of crystal structures are pointed out. (1) The term `lattice' is often used instead `structure'. (2) two terms `superlattice' and `sublattice' incorrectly interchanged. (3) Substructures composed a subset crystallographic orbits composing structure called `sublattices'. (4) Subperiodic referred to as `low-dimensional' structures.
Abstract A new classification in terms of the number independent twin elements is introduced and exploited to analyze symmetry multiple twins. The dichromatic point group description twins revised showing that, contrary what stated previous literature, all 58 groups represent possible some This approach extended polychromatic applied examples from recent literature.
The common classification of twinning into the four categories by merohedry (complete and exact overlap lattices twinned crystals), pseudomerohedry but approximate overlap), reticular (partial overlap) is revised in terms complete (translational point) lattice symmetry twin individual. new category polyholohedry introduced for twins where has same point a different orientation individual lattice. It shown that degeneration to index 1 relates, parallel way, metric syngonic merohedry. Some...
An algorithm is presented to derive the twin laws in non-merohedric twins through systematic search for quasi-perpendicular lattice planes/directions. The lattice, i.e. sublattice common whole crystalline edifice built by twinned individuals, based on a supercell of individual defined pair elements (hkl)/[uvw]. Starting from (real or supposed) element, (hkl) [uvw], set with user-defined limits index and obliquity explored. degree quasi-restoration commonly measured classical but some cases,...
High-spin states in $^{35}\mathrm{Ar}$ and $^{35}\mathrm{Cl}$ have been populated the $^{24}\mathrm{Mg}$($^{16}\mathrm{O}$, $\ensuremath{\alpha}n$) $\ensuremath{\alpha}p$) reactions, respectively, at a beam energy of 70 MeV. The comparison between level schemes these mirror nuclei shows striking asymmetry population yield high-spin analog positive parity, which indicates different intensities $E1$ transitions connecting positive- negative-parity structures both nuclei. Large differences are...