Coherent X‐Ray Scattering for the Hydrogen Atom in the Hydrogen Molecule

@article{Stewart1965CoherentXS,
  title={Coherent X‐Ray Scattering for the Hydrogen Atom in the Hydrogen Molecule},
  author={Robert F. Stewart and Ernest R. Davidson and William Turner Simpson},
  journal={Journal of Chemical Physics},
  year={1965},
  volume={42},
  pages={3175-3187}
}
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… 
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References

SHOWING 1-10 OF 13 REFERENCES
The Normal State of the Hydrogen Molecule
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. The
Hydrogen Atom Thermal Parameters
TLDR
The indicated trend for this compound, along with other results, provides the basis for a possible explanation of the anomolous values that have been obtained for hydrogen atom thermal parameters.
The Physical Nature of the Chemical Bond
The quantum mechanical wave functions of molecules are discussed. An attempt is made to effect a simultaneous regional and physical partitioning of the molecular density, the molecular pair density,
Natural Expansion of Exact Wavefunctions. II. The Hydrogen‐Molecule Ground State
The Kolos and Roothaan wavefunction for H2 has been analyzed into natural orbitals. It was found that the first natural orbital is nearly the SCF function. The first four natural orbitals provide a
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