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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A neutron diffraction study of xylitol: derivation of mean square internal vibrations for H atoms from a rigid-body description
TL;DR: A neutron diffraction study of xylitol shows that the carbon-oxygen skeleton conforms to a rigid-body (TLS) description and provides estimates of the internal vibrations of H atoms in a range of chemical environments.
Journal ArticleDOI
Synthesis, crystal structure, and molecular conformation of N-Boc-L-Phe-dehydro-Leu-L-Val-OCH3
TL;DR: The peptide N‐Boc‐ L‐Phe‐dehydro‐Leu‐L‐Val‐OCH3 was synthesized by the usual workup procedure and finally by coupling the N‐ Boc‐L •Phe •Leu–OH to valine methyl ester to show that the backbone adopts a β‐turn II conformation.
Journal ArticleDOI
Zirconium−Butadiene Bonded over a Planar Set of Oxygens Derived from Calix[4]arene and Its Behavior as a Source of Zirconium(II)
Alessandro Caselli,Luca Giannini,Euro Solari,Carlo Floriani,Nazzareno Re,Angiola Chiesi-Villa,Corrado Rizzoli +6 more
TL;DR: In this article, the first examples of butadienes bonded to a Zr−O matrix provided by a calix[4]arene skeleton and their reactivity were investigated.
Journal ArticleDOI
The molecular structures of gaseous tetramethylurea and tetramethylthiourea as determined by the electron-diffraction method
TL;DR: A pyramidal configuration about the N-atoms is found for both molecules with pyramid heights of 27.2 and 11.3 pm for tetramethylurea and tetramethythiourea, respectively as mentioned in this paper.
Journal ArticleDOI
Synthesis and crystal structure of cyclopentadienyl(1,4-dimethyl-1,4-dibora-2,5-cyclohexadiene)cobalt
TL;DR: In this article, the synthesis of the organometallic derivative cyclopentadienyl (1,4-dimethyl-1, 4-diboracyclohexa-2, 5-diene)cobalt is described.
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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