Journal ArticleDOI
Coherent X‐Ray Scattering for the Hydrogen Atom in the Hydrogen Molecule
TLDR
In this paper, the x-ray form factors for a bonded hydrogen in the hydrogen molecule have been calculated for a spherical approximation to the bonded atom, and the corresponding complex scattering factors have also been calculated.Abstract:
The x‐ray form factors for a bonded hydrogen in the hydrogen molecule have been calculated for a spherical approximation to the bonded atom. These factors may be better suited for the least‐squares refinement of x‐ray diffraction data from organic molecular crystals than those for the isolated hydrogen atom. It has been shown that within the spherical approximation for the bonded hydrogens in H2, a least‐squares refinement of the atomic positions will result in a bond length (Re value) short of neutron diffraction or spectroscopic values. The spherical atoms are optimally positioned 0.07 A off each proton into the bond. A nonspherical density for the bonded hydrogen atom in the hydrogen molecule has also been defined and the corresponding complex scattering factors have been calculated. The electronic density for the hydrogen molecule in these calculations was based on a modified form of the Kolos—Roothaan wavefunction for H2. Scattering calculations were made tractable by expansion of a plane wave in spheroidal wavefunctions.read more
Citations
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Journal ArticleDOI
Structure of the monoclinic form of cytidylic acid b.
Charles E. Bugg,Richard E. Marsh +1 more
TL;DR: The crystal structure of a monoclinic modification of cytidylic acid b (cytidine-3′-phosphate) has been determined and refined by three-dimensional X-ray diffraction techniques and the hydrogen-bonding scheme is different in the two modifications.
Journal ArticleDOI
Synthesis, electrochemistry, and magnetic properties of binuclear cobalt complexes containing the Co2(µ-X)(µ-carboxylato)2n+core (X = OH, Cl, or Br; n= 1–3). The crystal structures of [Co2II(µ-ClH2CCO2)2(µ-Cl)L2]PF6and [CoIICoIII(µ-MeCO2)2(µ-OH)L2][ClO4]2·0.5H2O (L =N,N′,N″-trimethyl-1,4,7-triazacyclononane)
TL;DR: In this article, a series of binuclear cobalt(II) complexes containing the µ-hydroxo-bis(µ-carboxylato)-dicobalt (II) core have been prepared where each cobalt center is capped by the tridentate macrocycle N,N′,N″-trimethyl-1,4,7-triazacyclononane (L, C9H21N3).
Journal ArticleDOI
Design of peptides: synthesis, crystal structure, molecular conformation, and conformational calculations of N-Boc-L-Phe-Dehydro-Ala-OCH3.
TL;DR: The low‐energy conformation found by calculations corresponds to the solid state conformation established by the crystal structure analysis and was refined by a full‐matrix least‐squares procedure to an R value of 0.048.
Journal Article
Electron population analysis of accurate diffraction data.V. Structure and one-center charge refinement of the light-atom mineral kernite, Na2B4O6(OH)2·3H2O
TL;DR: The structure of the mineral kernite has been investigated using a new set of accurate X-ray diffractometer data as discussed by the authors, and the results showed that the atomic densities in Kernite are described better by contracted Slater-type orbitals than by isolated atom Hartree-Fock orbitals.
Journal ArticleDOI
Experimental and Theoretical Charge Density Analysis of Polymorphic Structures: The Case of Coumarin 314 Dye
TL;DR: In this article, the experimental results are compared with the charge densities derived from multipole modeling of theoretical structure factors obtained from periodic quantum calculation with density functional theory (DFT) method and B3LYP/6-31G(d,p) level of theory.
References
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Journal ArticleDOI
The Physical Nature of the Chemical Bond
TL;DR: In this article, the quantum mechanical wave functions of molecules are discussed and an attempt is made to effect a simultaneous regional and physical partitioning of the molecular density, the molecular pair density, and the molecular energy, in such a way that meaningful concepts can be associated with the density and energy fragments thus formed.
Journal ArticleDOI
Accurate Electronic Wave Functions for the H 2 Molecule
W. Kolos,Clemens C. J. Roothaan +1 more
Journal ArticleDOI
The Problem of the Normal Hydrogen Molecule in the New Quantum Mechanics
TL;DR: The solution of Schroedinger's equation for the normal hydrogen molecule is approximated by the function $C[{e}^{\ensuremath{-}\frac{z({r}_{1}+{p}_{2})}{a}}+{e^{\ensem{-]-{m{e})+{m}−m{n}−n}]$ where m is the distance of one of the electrons to the two nuclei, and r is the distances of one electron to the other electron.
Journal ArticleDOI
The Normal State of the Hydrogen Molecule
TL;DR: In this paper, a simple wave function for the normal state of the hydrogen molecule, in which both the atomic and ionic configurations are taken into account, was set up and treated by a variational method.
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