Journal ArticleDOI
Generalized X-Ray Scattering Factors
TLDR
In this article, generalized x-ray scattering factors from the evaluation of Fourier transforms of atomic-orbital products have been determined from the analysis of X-ray diffraction data.Abstract:
Generalized x‐ray scattering factors have been determined from the evaluation of Fourier transforms of atomic‐orbital products. Self‐consistent‐field atomic orbitals for first‐row atoms have been studied. Analytical scattering expressions for rapid evaluation on digital computers have been developed. Scattering factors from small GTO expansions have been compared with both Clementi and Huzinaga SCF atomic orbitals. For one‐center orbital products, the three‐set GTO atomic orbitals agree with full SCF scattering factors to within five parts per hundred or better; the four‐set GTO expansions have relative differences of 1.5% or less. For the two‐center scattering cases, three or more Gaussians per atomic orbital yield relative errors less than 1%. The generalized x‐ray scattering factors can serve as basis functions in the analysis of charge densities from x‐ray diffraction data.read more
Citations
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Molden: a pre- and post-processing program for molecular and electronic structures.
Gijs Schaftenaar,Jan H. Noordik +1 more
TL;DR: Molden is a software package for pre- and postprocessing of computational chemistry program data that features different options to display MOLecular electronic DENsity, each focusing on a different structural aspect: molecular orbitals, electron density, molecular minus atomic density and the Laplacian of the electron density.
Journal ArticleDOI
Small Gaussian Expansions of Slater‐Type Orbitals
TL;DR: In this article, small Gaussian expansions of Slater-type orbitals by the method of least squares are presented and the least square equations are solved by a full-matrix method.
Journal ArticleDOI
Wavefunctions derived from experiment. I. Motivation and theory.
TL;DR: The wavefunction fitting method is illustrated by developing the theory for extracting a single-determinant wavefunction for a fragment of a molecular crystal, using data obtained from elastic X-ray scattering data.
Journal ArticleDOI
On the origin of topological differences between experimental and theoretical crystal charge densities
TL;DR: Topological analysis of experimental and theoretical (molecular and crystal) electron densities of p-nitroaniline and p-amino-p'-nitrobiphenyl reveals considerable discrepancies between experiment and theory for the bond critical points properties.
Journal ArticleDOI
Meaningful Structural Descriptors from Charge Density
TL;DR: This article tries to demonstrate how charge density analyses can shed light on aspects of chemical bonding and reactivity resulting from the determined bonding situation and sets the scene for new unconventional synthetic approaches.
References
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Journal ArticleDOI
Coherent X‐Ray Scattering for the Hydrogen Atom in the Hydrogen Molecule
TL;DR: 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.
Journal ArticleDOI
Small Gaussian Expansions of Atomic Orbitals
TL;DR: Expansions of Clementi STO SCF AO's for some first-row atoms with GTO's have been obtained by the method of least squares as mentioned in this paper, where expansion lengths vary from two to five Gaussians for each AO.
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X-ray scattering by aggregates of bonded atoms. III. The bond scattering factor: simple methods of approximation in the general case
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A general structure factor formalism for interpreting accurate X-ray and neutron diffraction data
TL;DR: In this paper, the analysis of X-ray and neutron diffraction data in accurate studies of crystal and molecular structure requires the development of a new structure factor formalism, which recognizes antisymmetric features associated with nonspherical atomic charge distributions and with anharmonic components of the atomic vibration amplitudes.
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Atomic scattering factors for spherical and aspherical charge distributions
TL;DR: In this paper, a general formalism for calculating the coherent scattering of x-rays from nonspherical charge distributions as a function of atomic orientation is presented, based in part on group theoretic methods.