Fourier Hadamard And Hilbert Transforms In Chemistry

In virtually all types of experiments in which a response is analyzed as a function of frequency (e. g. , a spectrum), transform techniques can significantly improve data acquisition and/or data reduct ion. Research-level nuclear magnet ic resonance and infra-red spectra are already obtained almost exclusively by Fourier transform methods, because Fourier transform NMR and IR spectrometers have been commercially available since the late 1960·s. Similar transform techniques are equally valuable (but less well-known) for a wide range of other chemical applications for which commercial instruments are only now becoming available: for example, the first corrmercial Fourier transform mass spectrometer was introduced this year (1981) by Nicolet Instrument Corporation. The purpose of this volume is to acquaint practicing chemists with the basis, advantages, and applica of Fourier, Hadamard, and Hilbert transforms in chemistry. For tions almost all chapters, the author is the investigator who was the first to apply such methods in that field. The basis and advantages of transform techniques are described in Chapter 1. Many of these aspects were understood and first applied by infrared astronomers in the 1950·s, in order to improve the otherwise unacceptably poor signal-to-noise ratio of their spec tra. However, the computations required to reduce the data were painfully slow, and required a 1 arge computer.

The application of the Fourier transform is being seen to an increasing extent in all branches of chemistry, but it is in the area of chemical analysis that the greatest activity is taking place. Fourier transform infrared and nuclear magnetic resonance spectrometry are already routine methods for obtaining high-sensitivity IR and NMR spectra. Analogous methods are now being developed for mass spectrometry (Fourier transform ion cyclo tron resonance spectrometry) and microwave spectroscopy, and Fourier transform techniques have been successfully applied in several areas of electrochemistry. In addition the fast Fourier transform algorithm has been used for smoothing, interpolation, and more efficient storage of data, and has been studied as a potential method for more efficient identification of samples using pattern recognition techniques. Linear transforms have also been shown to be useful in analytical chemistry. Probably the most important of these is the Hadamard transform, which has been applied in alternative methods for obtaining IR and NMR data at high sensitivity. Even though measurements involving this algorithm will probably not be applied as universally as their Fourier transform ana logs, in the area of pattern recognition application of the Hadamard trans form will in all probability prove more important than application of the Fourier transform.

The definitive reference on Hilbert transforms covering the mathematical techniques for evaluating them, and their application.

Mathematics for Physical Chemistry, Third Edition, is the ideal text for students and physical chemists who want to sharpen their mathematics skills. It can help prepare the reader for an undergraduate course, serve as a supplementary text for use during a course, or serve as a reference for graduate students and practicing chemists. The text concentrates on applications instead of theory, and, although the emphasis is on physical chemistry, it can also be useful in general chemistry courses. The Third Edition includes new exercises in each chapter that provide practice in a technique immediately after discussion or example and encourage self-study. The first ten chapters are constructed around a sequence of mathematical topics, with a gradual progression into more advanced material. The final chapter discusses mathematical topics needed in the analysis of experimental data. Numerous examples and problems interspersed throughout the presentations Each extensive chapter contains a preview, objectives, and summary Includes topics not found in similar books, such as a review of general algebra and an introduction to group theory Provides chemistry specific instruction without the distraction of abstract concepts or theoretical issues in pure mathematics

Written by spectroscopists for spectroscopists, here is a book which is not only a valuable handbook and reference work, but also an ideal teaching text for Fourier transform methods as they are applied in spectroscopy. It offers the first unified treatment of the three most popular types of FT/spectroscopy, with uniform notation and complete indexing of specialized terms. All mathematics is self-contained, and requires only a knowledge of simple calculus. The main emphasis is on pictures and physical analogs rather than detailed algebra. Instructive problems, presented at the end of each chapter, offer extensions of the basic treatment. Solutions are given or outlined for all problems. The book offers a wealth of practical information to spectroscopists. Non-ideal effects are treated in detail: noise (source- and detector-limited); non-linear response; limits to spectrometer performance based on finite detection period, finite data size, mis-phasing, etc. Common puzzles and paradoxes are explained: e.g. use of mathematically complex variables to represent physically real quantities; interpretation of negative frequency signals; on-resonance vs. off-resonance response; interpolation (when it helps and when it doesn't); ultimate accuracy of the data; differences between linearly- and circularly-polarized radiation; multiplex advantage or disadvantage, etc. Chapter 1 introduces the fundamental line shapes encountered in spectroscopy, from a simple classical mass-on-a-spring model. The Fourier transform relationship between the time-domain response to a sudden impulse and the steady-state frequency-domain response (absorption and dispersion spectra) to a continuous oscillation is established and illustrated. Chapters 2 and 3 summarize the basic mathematics (definitions, formulas, theorems, and examples) for continuous (analog) and discrete (digital) Fourier transforms, and their practical implications. Experimental aspects which are common to the signal (Chapter 4) and noise (Chapter 5) in all forms of Fourier transform spectrometry are followed by separate chapters for treatment of those features which are unique to FT/MS, FT/optical, FT/NMR, and other types of FT/spectroscopy. The list of references includes both historical and comprehensive reviews and monographs, along with articles describing several key developments. The appendices provide instant access to FT integrals and fast algorithms as well as a pictorial library of common Fourier transform function pairs. The comprehensive index is designed to enable the reader to locate particular key words, including those with more than one name.

The intent of this book a collection of manuscripts - is to provide general descriptions of analytical techniques which we believe to be useful to the biological scientist, and to provide examples of the utility of each technique. The contributing authors were asked to focus on examples in which their particular technique has proven particularly useful in studies of biological systems. Many commonly used analytical techniques such as NMR and ESR are not included in this work, it is preferred to focus on techniques which perhaps have not received as much coverage as in the recent literature. All of the analytical tools covered in this volume have great utility, and the scientific community can expect to see increasing usage of most if not all of these techniques.

The analytical power of ion mobility spectrometry-mass spectrometry (IMS-MS) instruments is poised to advance this technology from research to analytical laboratories. Exploring these developments at this critical juncture, Ion Mobility Spectrometry-Mass Spectrometry: Theory and Applications covers the tools, techniques, and applications involved w

This volume is a collection of contributions to the FT-IR Workshop held under the auspices of the Spectroscopy Society of Canada and organ ized by Professor Theophile Theophanides, Director of the Workshop. The gathering of leading spectroscopists and researchers at Gray Rocks to discuss .Fourier Transform Infrared Spectroscopy was the occasion of the 29th Annual Conference of the Spectroscopy Society of Canada. The plea sant surroundings of Gray Rocks, St-Jovite, Quebec, Canada contributed most positively to the success of the two-day Workshop held September 30, October 1, 1982. The preliminary program and the proceedings were distributed at the Workshop by Multiscience Publications Ltd. The publication of this volume provides the occasion to thank all the contributors for kindly accepting to lecture at the Workshop and for their collaboration. I thank Mr. AI. Dufresne for accepting to act as manager of the Workshop and Mrs. Susane Dufresne secretary of the Work shop for patiently contacting all the participants and for making the necessary arrangements of registration and accomodation.