Water-mediated bond formation: The structure of the peptide GPG-NH2 has been investigated in aqueous solution to understand the role of water in the formation of a β-turn. Using a combination of neutron diffraction enhanced by isotopic substitution, NMR spectroscopy, and computer simulations, it was found that water is an essential component to initiate folding in solution.

Globular molecules of 1-chloroadamantane form a plastic phase in which the molecules rotate in a restrained way, but with their centers of mass forming a crystalline ordered lattice. Plastic phases can be regarded as test cases for the study of disordered phases since, contrary to what happens in the liquid phase, there is a lack of stochastic translational degrees of freedom. When the temperat...

New BaMnPnF (Pn = As, Sb, Bi) are synthesized by stoichiometric reaction of elements with BaF₂. They crystallize in the P4/nmm space group, with the ZrCuSiAs-type structure, as indicated by X-ray crystallography. Electrical resistivity results indicate that Pn = As, Sb, and Bi are semiconductors with band gaps of 0.73 eV, 0.48 eV and 0.003 eV (extrinsic value), respectively. Powder neutron diff...

Peptide groups are generally assumed to be planar in protein structure, due to 'rigid' partial double bond character of peptide bonds, thus the value of peptide torsion angle omega should be restricted to 180 degrees for the usual trans form of peptide unit. However, on analyzing the ultra-high resolution protein crystal database, we find that in some cases, omega deviates >10 degrees from its ...

Layered borocarbides RB2C (R=Dy, Ho, and Er) have been studied by powder neutron diffraction at 2-30 K. ErB2C has two-sublattice antiferromagnetic order below T(N)=16.3 K, but DyB2C and HoB2C show a coexistence of a conventional canted k=(000) ferromagnetic structure and unconventional magnetic correlations. The k=(000) phase orders at T(c)=8.5 K (DyB2C) and 7.1 K (HoB2C), but low-Q diffraction...

The peak profile shape analysis has been preferentially used in evaluation of X-ray and synchrotron powder diffraction pattern. However, neutron diffraction facilities of new generation frequently offer the instrumental resolution high enough to study efficiently the effects of broadening of neutron diffraction profiles. The present paper describes the procedure for a detailed evaluation of Bra...

The Neutron Larmor diffraction method is applied for the first time to determine absolute lattice spacing of a Silicon powder and polycrystalline IN718 samples. The absolute value of lattice spacing can be measured to an accuracy of 7· 10A. However, absolute determination of the lattice parameter is limited by the quality of the reference specimen used. Absolute lattice spacing determined by La...

Recently strong electric fields (up to 10 V/cm) have been discovered, which affect the neutrons moving in noncentrosymmetric crystals. Such fields allow new polarization phenomena in neutron diffraction and optics and provide, for instance, a new feasibility of a search for the neutron electric dipole moment (EDM). A strong interplanar electric field of the crystal and a sufficiently long time ...