Accession Number : ADA296636

Title :   A Quantitative Study of Langmuir-Blodgett Model Systems by High Resolution Electron Energy Loss Vibrational Spectroscopy. Spectral Analysis and Information Depth.

Descriptive Note : Technical rept.,

Corporate Author : STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY

Personal Author(s) : Weitzsacker, Cara L. ; Gardella, Joseph A., Jr. ; Gregoire, Chantal ; Pireaux, Jean-Jacques

PDF Url : ADA296636

Report Date : MAR 1995

Pagination or Media Count : 41

Abstract : Langmuir Blodgett monolayers of a series of anthroyl substituted alkanoic (fatty) acid derivatives are used as model systems to study the interaction of low energy electrons with organic polymers in high resolution electron energy loss spectrometry. The variation of structure in the series effectively places the anthroyl functionality at various depths from the monolayer vacuum surface. The HREELS analysis of these systems provides a means to probe the depth dependence of vibrational energy losses. Maximum likelihood spectral restoration was used to establish more precise and energies resulting from energy loss, with comparison to infrared and Raman spectroscopic results from the compounds. These band energies were then used as initial values for curve fitting of the original data. The results of curve resolution aided in the estimation of the relative intensity of vibrational bands specific to the functional groups in the anthroyl sidechain and the aliphatic hydrocarbon backbone of the molecules in the films. By comparing vibrational intensities normalized to the elastic peak, it is shown that bands due to CH vibrations from saturated aliphatic structures are more surface sensitive than those due to aromatic structures. The comparison of the series of samples shows how the signals from aromatic structures decrease relative to aliphatic over a range of 15 A from the vacuum surface. jg p.1

Descriptors :   *HIGH RESOLUTION, PEAK VALUES, MODELS, LAYERS, MOLECULES, POLYMERS, RAMAN SPECTROSCOPY, COMPARISON, GRAPHS, STRUCTURES, ELASTIC PROPERTIES, INTENSITY, VACUUM, ALIPHATIC COMPOUNDS, DEPTH, SATURATION, VARIATIONS, SURFACES, ELECTRONS, ELECTRON ENERGY, FREQUENCY BANDS, LOW ENERGY, HYDROCARBONS, PRECISION, ORGANIC COMPOUNDS, MOLECULAR STRUCTURE, LOSSES, AROMATIC COMPOUNDS, INFRARED RADIATION, ENERGY BANDS, SPECTRUM ANALYSIS, FATTY ACIDS, CURVE FITTING, VIBRATIONAL SPECTRA.

Subject Categories : Physical Chemistry
      Organic Chemistry
      Polymer Chemistry
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE