Electron Diffraction Study of the Structure of Trimethylphosphine

The structural parameters of gaseous trimethylphosphine, including standard errors, were found to be as follows: center of gravity bond distances were rCP=1.8465±0.003 A, and rCH=1.091±0.006 A; angles were <C☒P☒C=98.6±0.3°, and <P☒C☒H=110.7±0.5°; root‐mean‐square amplitudes of vibration were lCP=0.054±0.003 A, lCH=0.073±0.006 A, lP— —H=0.110±0.006 A, and lC— —C=0.084±0.005 A. The methyl groups were observed to be in staggered configurations analogous to those in ethane, with rotational barriers probably 1.5 kcal/mole or higher. A brief structural comparison with halogen derivatives and hydrides is presented.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70229/2/JCPSA6-32-2-512-1.pd

Structures of CF3Cl and CH3Cl

The molecular structures of CF3Cl and CH3Cl were determined by refined procedures of electron diffraction. For CF3Cl, the most probable C☒F and C☒Cl distances are 1.328 A and 1.751 A respectively and ∠FCF=108.6°. Results for CH3Cl agree with the complete microwave determination. Vibrational amplitudes are in agreement with approximate calculations by Morino.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70122/2/JCPSA6-23-10-1860-1.pd

The Interpretation of Electron Diffraction Patterns from Hydrocarbon Films

The theoretical expressions previously derived for the scattering of electrons by oriented hydrocarbon chains have been extended and applied to the calculation of characteristic diffraction patterns. These patterns are analyzed to form a basis for obtaining information about the molecular orientation. For the long chain molecules, the azimuthal direction, and the declination from the vertical may be determined independently. The orientation of the hydrocarbon chain about its own axis is less easily established, since it is determined only from the intensity distribution within the separate diffraction orders. When the declination is sufficiently large, randomness in the azimuthal directions is distinguished by the crossed‐line pattern obtained. Randomness in the declination from the vertical may be estimated from the irregular spacing of the intercepts of the crossed lines. Quantitative intensity data would permit a more precise study of the angular distribution of the declination, and also of the orientation of the hydrocarbon chain about its own axis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70890/2/JCPSA6-15-5-213-1.pd

Electron Diffraction and the Molecular Structure of Gases. The Crystal Structure of Chalcopyrite

An apparatus has been developed for the study of the molecular structure of gases by the electron diffraction method. A number of improved features in the construction are described. The method has been applied to an investigation of the resonance among the possible electronic structures of the Lewis type and also of the atomic configurations in certain molecules. Diacetylene and cyanogen are found to be linear, contrary to a published report of evidence for a model with 150° bond angles. Methyl azide is found to have a linear azide group. The ring model which has been proposed is shown to be eliminated. The ring model for carbon suboxide has also been eliminated in favor of a linear model. Chlorine dioxide shows evidence for the existence of the three-electron bond, and this fact explains its lack of tendency to polymerize to Cl2O4. The hexafluoride of sulfur, selenium and tellurium are found to have structures which may be represented by a regular octahedron with six atoms at the corners surrounding the central atom. The interatomic distances for all of the above compounds are reported. The crystal structure of chalcopyrite has been re-investigated and the correct structure is reported.</p

Refined Procedure for Analysis of Electron Diffraction Data and Its Application to CCl4

A refined procedure for obtaining the structure of free molecules from electron diffraction data is described which compensates for the interference arising from non‐nuclear scattering. The procedure is applied to CCl4 using somewhat more extensive rotating sector data than has hitherto been published for this molecule. Estimates are made for the first time in electron diffraction results of the effect of anharmonicity of vibration on the measurement of internuclear distance and of the effect of the failure of the Born approximation on the measurement of amplitudes of vibration. A method of estimating the reliability of the results is described.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71343/2/JCPSA6-23-10-1854-1.pd

Electron diffraction study of oleophobic films on copper, iron and aluminum

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32561/1/0000686.pd

Variation of contact angle and structure with molecular length and surface density in adsorbed films of fatty acids

Films of fatty acids from 12 to 22 carbons were prepared by adsorption on glass microscope slides from cetane solutions. Variations in density were achieved (1) by using a range of concentrations with a fixed short time of immersion and (2) by subsequent immersion in cetane of the most dense films.Electron diffraction patterns showed an increasing average tilt of the molecules relative to the surface normal with decreasing length of the molecules but no apparent change in tilt with variations in surface density. The contact angles exhibited by drops of cetane on the films decreased markedly from a maximum of 43-44[deg] when the density of the adsorbed molecules on the surface was decreased, but were independent of the variations in tilt and length of the molecules.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32519/1/0000610.pd

The oxidation of thin single crystals of copper ; technical progress report.

http://deepblue.lib.umich.edu/bitstream/2027.42/3848/5/bab3083.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/3848/4/bab3083.0001.001.tx

The oxidation of thin single crystals of copper ; final report.

http://deepblue.lib.umich.edu/bitstream/2027.42/3849/5/bab3083.0002.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/3849/4/bab3083.0002.001.tx

The Calibration of Photographic Emulsions for Electron Diffraction Investigations

A procedure for calibrating photographic emulsions has been devised which measures the deviation from linearity of the curve relating electron exposure to optical density. The experimental application of this procedure is found to give results consistent with a very simple model of the exposure process. It is also noted that the sensitivity of a photographic plate increases with increasing distance from the center of the plate. Measurements of this effect are given.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69408/2/JAPIAU-24-5-656-1.pd