Charge density and correlation study of atoms and molecules by high-energy electron scattering

Miscellaneous · Sun Jan 01 00:00:00 EST 1989

OSTI ID:5665689

Zhang, Y

Energy resolved differential scattering cross sections of high energy electrons and small molecules were measured during the course of this study. The coherent X-ray scattering form factors, which can be derived from the electron scattering experiments, are directly related to the charge density distributions of the target molecules. The difference between the data and the calculations based on the independent atom model, which is based on a combination of the constituent atoms with spherical atomic charge densities positioned with the known geometrical configuration, is a measure of the charge redistribution in the molecule when the chemical bond is formed. Although the transformation from the scattering factors to the three-dimensional charge density map is not unique, the inverse transformation is. With the precision of the experiment (0.1%), the correlation effect in the target molecules can also be studied. This provides a further evaluation of the configuration interaction calculations. The separation of the elastic and inelastic scattering makes the independent investigations of the coherent and incoherent X-ray scattering form factors as well as the electronic interaction energies in the molecules possible. The differential scattering cross sections of CH{sub 4}, H{sub 2}, N{sub 2} and O{sub 2} were measured and the derived properties listed above were studied. The scattering cross sections at very small scattering angles are related to the molecular quadruple moments, the diamagnetic susceptibilities and other measurable moments. For the first time, the scattering behaviors of H{sub 2}, N{sub 2} and O{sub 2} at small angles were measured with high precision and the moment evaluation was performed.

• Research Organization: Texas Univ., Austin, TX (United States)
• OSTI ID: 5665689
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ELECTRON-MOLECULE COLLISIONS
SCATTERING
HYDROGEN
METHANE
NITROGEN
OXYGEN
CHARGE DENSITY
CONFIGURATION INTERACTION
CORRELATIONS
DIFFERENTIAL CROSS SECTIONS
ELASTIC SCATTERING
FORM FACTORS
INELASTIC SCATTERING
SMALL ANGLE SCATTERING
TRANSFORMATIONS
WAVE FUNCTIONS
ALKANES
COLLISIONS
CROSS SECTIONS
ELECTRON COLLISIONS
ELEMENTS
FUNCTIONS
HYDROCARBONS
MOLECULE COLLISIONS
NONMETALS
ORGANIC COMPOUNDS
PARTICLE PROPERTIES
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena