CAREER: Determination of Glass Structure using Laser Induced Time of Flight Mass Spectroscopy

点击翻译按钮获取中文摘要

9733724 Affatigato The Faculty Early Career Development project will use laser induced time-of-flight mass spectroscopy (LITOF-MS) to determine the short- and intermediate-range order of boron oxide-based glass systems. It is known that the network of pure boron oxide glass contains hexagonal rings of three-coordinated boron. Disagreement exists, however, regarding what fraction of the boron present in the glass is tied up in these rings. The straightforward deconvolution of time-of-flight mass spectra will yield valuable information regarding the presence of larger structural units in this glass, as well as quantitative data on the abundance of the ring groupings. Alkali borate glasses can be made up of a variety of larger groups, including chains and hexagonal rings linked by four-coordinated borons. The presence and relative abundance of these larger units in alkali borate glasses of varying compositions will be measured using the mass spectrometer. Crystals of the same stoichiometry will be investigated and used as starting points for calibration and analysis. During this stage of the project, the effect of dopants (chromophores introduced into the glass at concentrations below 1 molar percent) on the yield of network groupings upon laser irradiation will be examined. In the last stage of the project, the LITOF-MS will be used to study alkali borosilicate glasses. It is generally agreed that these glasses are made up mostly of silicate and borate sub-networks, but questions remain about the effect of dopants and if there is interaction between the two networks. NMR data yields contradictory evidence on these matters, but the LITOF-MS should provide data that can answer these questions. As Coe College is a primarily undergraduate institution, the work will be carried out with undergraduate students, providing them a rare long-term researc h exposure to cutting-edge work in materials science. The students will carry out the sample manufacture and characterization, as well as the time of flight measurements. In addition, outreach programs will bridge the gap between the College and the local high schools. The upper-level physics and chemistry classes of two nearby high schools will be brought on campus for yearly visits and seminars on careers in science and engineering, and will have several opportunities to interact with the undergraduate researchers. %%% This CAREER project will seek to answer several fundamental questions about boron oxide-based glasses using laser induced time-of-flight mass spectroscopy (LITOF-MS) to examine the short- and intermediate-range atomic arrangements. The project will help us understand the structure of these technologically important materials. The involvement of undergraduate students in the performance of the research will provide them with experience in materials research. ***