First spin-resolved electron distributions in crystals from combined polarized neutron and X-ray diffraction experiments

Deutsch, Maxime; Gillon, B.; Claiser, Nicolas; Gillet, Jean‐Michel; Lecomte, Claude; Sarwat, Mohamed

doi:10.1107/s2052252514007283

Cited by 47 publications

(57 citation statements)

References 16 publications

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“…[11][12][13][14][15] The multipole model is the result of necessary approximations. [23] Cross-fertilized by charge-density research, ways of directly fitting the shapes of orbitals andw avefunctions to the mea-sured diffraction pattern were also devised. [16] Furthermore, the modeling of atomicd isplacements initially led to additional problems in case of two-center electron density functions.…”

Section: Introductionmentioning

confidence: 99%

Quantum Crystallography: Current Developments and Future Perspectives

Genoni

Bučinský

Claiser

et al. 2018

Chemistry A European J

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Crystallography and quantum mechanics have always been tightly connected because reliable quantum mechanical models are needed to determine crystal structures. Due to this natural synergy, nowadays accurate distributions of electrons in space can be obtained from diffraction and scattering experiments. In the original definition of quantum crystallography (QCr) given by Massa, Karle and Huang, direct extraction of wavefunctions or density matrices from measured intensities of reflections or, conversely, ad hoc quantum mechanical calculations to enhance the accuracy of the crystallographic refinement are implicated. Nevertheless, many other active and emerging research areas involving quantum mechanics and scattering experiments are not covered by the original definition although they enable to observe and explain quantum phenomena as accurately and successfully as the original strategies. Therefore, we give an overview over current research that is related to a broader notion of QCr, and discuss options how QCr can evolve to become a complete and independent domain of natural sciences. The goal of this paper is to initiate discussions around QCr, but not to find a final definition of the field.

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Section: Introductionmentioning

confidence: 99%

Quantum Crystallography: Current Developments and Future Perspectives

Genoni

Bučinský

Claiser

et al. 2018

Chemistry A European J

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123

114

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“…Previous work has shown that spin-resolved electron density can be modelled using joint refinement against X-ray, neutron and polarized neutron diffraction data [16]. While PND gives access to the spin density in the position space, M-ICS permits to explore the spin density in the momentum space.…”

Section: Introductionmentioning

confidence: 99%

Spin density in YTiO3 : I. Joint refinement of polarized neutron diffraction and magnetic x-ray diffraction data leading to insights into orbital ordering

et al. 2017

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Orbital ordering below 30 K was previously observed in the ferromagnetic Y T iO3 compound both by polarized neutron diffraction (PND) and X-ray magnetic diffraction (XMD). In this paper we report a new procedure for the joint refinement of a unique spin density model based on both PND and XMD data. The distribution of the unpaired 3d-electron of titanium is clearly seen on the magnetization density reconstructed by the Maximum of Entropy Method from the PND data collection at 5 K. The T i 3+ 3d orbital populations obtained by joint model refinement are discussed in terms of the orbital ordering scheme. Small but significant magnetic moments on apical oxygen O1 and yttrium atoms are found. The agreement between experimental and theoretical spin densities obtained using density functional theory is discussed.

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“…However, the significant breakthrough was achieved recently by combination of the results coming from different experiments using X-ray, neutron and polarized neutron diffracttion data on spin resolved electron density [19]. These experimental spin up and spin down densities compare well with density functional theory (DFT).…”

Section: Advanced and New Methods And Technologies Supporting The Devmentioning

confidence: 57%

A century of X-ray crystallography and 2014 international year of X-ray crystallography

Kojić‐Prodić

2015

Maced. J. Chem. Chem. Eng.

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The 100 th anniversary of the Nobel prize awarded to Max von Laue in 1914 for his discovery of diffraction of X-rays on a crystal marked the beginning of a new branch of science -X-ray crystallography. The experimental evidence of von Laue's discovery was provided by physicists W. Friedrich and P. Knipping in 1912. In the same year, W. L. Bragg described the analogy between X-rays and visible light and formulated the Bragg's law, a fundamental relation that connected the wave nature of X-rays and fine structure of a crystal at atomic level. In 1913 the first simple diffractometer was constructed and structure determination started by the Braggs, father and son. In 1915 their discoveries were acknowledged by a Nobel Prize in physics. Since then, X-ray diffraction has been the basic method for determination of three-dimensional structures of synthetic and natural compounds. The three-dimensional structure of a substances defines its physical, chemical, and biological properties. Over the past century the significance of X-ray crystallography has been recognized by about forty Nobel prizes. X-ray structure analysis of simple crystals of rock salt, diamond and graphite, and later of complex biomolecules such as B12-vitamin, penicillin, haemoglobin/myoglobin, DNA, and biomolecular complexes such as viruses, chromatin, ribozyme, and other molecular machines have illustrated the development of the method. Among these big discoveries the double helix DNA structure was an epochal achievement of the 20 th century. These discoveries, together with many others of the X-ray crystallography, have completely changed our views and helped to develop other new fields of science such as molecular genetics, biophysics, structural molecular biology, material science, and many others. During the last decade, the implementation of free electron X-ray lasers, a new experimental tool, has opened up femtosecond dynamic crystallography. This highly advanced methodology enables to solve the structures and dynamics of the most complex biological assemblies involved in a cell metabolism. The advancements of science and technology over the 20 th and 21 st centuries are of great influence on our views in almost all human activities. The importance of Xray crystallography for science and technology advocates for its high impact on a wide area of research and declares it as a highly interdisciplinary science. In short, crystallography has defined the shape of the modern world.Focusing on single crystal diffraction, this essay tackles only one field of crystallography; the comprehensive review on X-ray crystallography can hardly be fitted into a single article. The aim with this review was to highlight the most striking examples illustrating some of the milestones over the past century.Keywords: centennial anniversary of X-ray crystallography; discovery of X-ray crystallography -dazzling history; highlights; X-ray structure analysis and its prospect Тридимензионалната структура на супстанците ги дефинира нивните физички, хемиски и биолошки својс...

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First spin-resolved electron distributions in crystals from combined polarized neutron and X-ray diffraction experiments

Abstract: A method to map spin-resolved electron distribution from combined polarized neutron and X-ray diffraction is described and applied for the first time to a molecular magnet and it is shown that spin up density is 5% more contracted than spin down density.

Cited by 47 publications

References 16 publications

Quantum Crystallography: Current Developments and Future Perspectives

Quantum Crystallography: Current Developments and Future Perspectives

Spin density in YTiO3 : I. Joint refinement of polarized neutron diffraction and magnetic x-ray diffraction data leading to insights into orbital ordering

A century of X-ray crystallography and 2014 international year of X-ray crystallography

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