FTMW/CVI: FOURIER TRANSFORM MICROWAVE / COHERENCE SPECTROSCOPY WITH VIRTUAL INSTRUMENTS
Date
2001
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
Modern Fourier transform microwave (FTMW) spectroscopy, first implemented as an impulse excitation technique in a steady gas-waveguide $apparatus^{a}$, started only a quarter of a century ago. Soon after, the method was supplemented for special applications, e.g. Stark-$effect^{b}$, double $resonance^{c}$, and $2D^{d}$ spectroscopy. The subsequent implementation of the technique in a supersonic jet-resonator $apparatus^{e}$ was followed by similar developments, i.e. Stark-$effect^{f}$, double $resonance^{g}$, laser $ablation^{h}$, and $DC-discharge^{i}$. $Automation^{j}$ along with the ``coaxially oriented beam-resonator $arrangement""^{k}$ (COBRA) has greatly increased efficiency, resolution, and sensitivity of current FTMW spectrometers. We present the implementation of a complete COBRA-FTMW spectrometer featuring the capabilities given above. The entire experiment is operated, either interactivle or automatically, by a graphical user interface (GUI)-based program which is capable of waveguide and resonator applications. Developed in the C programming language, while following the concept of virtual instruments (VI), the software can co-operate with a wide variety of PCI and IEEE hardware components to build the instrument. Only one application specific logic circuit, which will also be presented, is needed.
Description
$^{a}$J. Ekkers and W. H. Flygare, Rev. Sci. Instrum. 47, 448(1976). $^{b}$G. Bestmann and H. Dreizler, Z. Naturforsch. 37a, 615(1982). $^{c}$H. Dreizler, E. Fliege, H. M\""ader, and W. Stahl, Z. Naturforsch. 37a, 1266(1982). $^{d}$D. A. Andrews and J. G. Baker, J. Phys. B20, 5705(1987). $^{e}$T. J. Balle and W. H. Flygare, Rev. Sci. Instrum. 52, 33(1981). $^{f}$L. H. Coudert, F. J. Lovas, R. D. Suenram, and J. T. Hougen, J. Chem. Phys. 87, 6290(1987). $^{g}$L. Martinache, S. Jans-B\""urli, B. Vogelsanger, W. Kresa, and A. Bauder, Chem. Phys. Lett. 149, 424(1988). $^{h}$R. D. Suenram, F. J. Lovas, and K. Matsumura, Ap. J. Lett. 342, L103(1989). $^{i}$J.-U. Grabow, N. Heineking, and W. Stahl, Z. Naturforsch. 46a, 914(1991). $^{j}$U. Andresen, H. Dreizler, J.-U. Grabow and W. Stahl, Rev. Sci. Instrum. 61, 3694(1990). $^{k}$J.-U. Grabow and W. Stahl, Z. Naturforsch. 45a, 1043(1990)
Author Institution: Institut f\""ur Physikalische Chemie und Elektrochemie
Author Institution: Institut f\""ur Physikalische Chemie und Elektrochemie