Jerry Workman

The state of multivariate thinking for scientists in industry: 1980–2000

Abstract Chemometrics has enjoyed tremendous success in the areas related to calibration of spectrometers and spectroscopy-based measurements. These chemometric-based spectrometers have been widely applied for process monitoring and quality assurance. However, chemometrics has the potential to revolutionize the very intellectual roots of problem solving. Are there barriers to a more rapid proliferation of chemometric-based thinking, particularly in industry? What are the potential effects of chemometrics technology and the New Network Economy (NNE) working in concert? Who will be the winners in the race for faster, better, cheaper systems and products? These questions are reviewed in terms of the principles of the NNE and in the promise of chemometrics for industry. What then is the state of multivariate thinking in industry? Several powerful principles are derived from an evaluation of the NNE and chemometrics which could allow chemometrics to proliferate much more rapidly as a key general problem-solving tool.

7 - Spectroscopy of Solids

This chapter provides an overview of the instrumentation and measurement phenomena relative to the spectroscopy of solids. The spectroscopy of solids is defined as the qualitative or quantitative measurement of the interaction of electromagnetic radiation (EMR) with atoms or molecules in the solid state. The EMR interacts as scattering, absorption, reflectance, or emission with solid matter. The purpose of spectroscopy is to quantify or qualify these interactions by the use of a variety of photon-producing and photon-detection devices. The physics of these interaction phenomena and devices is presented in the chapter. A variety of spectrometer configurations are used to optimize the measurements of electromagnetic radiation as it interacts with solid matter. The measurement of solids using spectroscopy involves a myriad of physical phenomena is also summarized in the chapter.

Review of Interpretive Spectroscopy For Raman and Infrared

This chapter discusses interpretive spectroscopy for infrared and Raman spectra. Fundamental frequencies that are characteristics of groups of atoms (termed functional groups) with common group names and general infrared locations (in wavenumbers) are also discussed. The chapter also discusses the fingerprint frequencies that occur because of interactions of the molecular vibrations of the entire molecule rather than specific functional groups. Because the infrared spectrum is unique to an individual molecule, it is termed the fingerprint of that molecule, much as the fingerprint of a person indicates the specific identity of that person. However, in identifying the unique “fingerprint vibrations” of a molecule, information is presented as to the approximate molecular formula and composition of the molecule. The chapter then discusses coupling of vibrations, which indicates that the oscillators, or molecular vibrations of two or more molecules, are interactive. Therefore, the original vibrational energy states (if the vibrations could occur independently of one another) result in split energy states due to the interaction of the vibrations. Coupling is divided into two basic orders, first and second (Fermi resonance). These are explained in the chapter.

Functional Groupings and Calculated Locations in Wavenumbers (cm -1 ) for IR Spectroscopy

This chapter presents the functional groupings for infrared (IR) spectroscopy. The groups discussed include C–H stretch, C–H bend, C–C stretch, carbonyl group, carboxylic acids, anhydrides, acyl halides, amides, alcohols and phenols (O–H stretch), amides (N–H stretch), unsaturated N compounds (C=N stretch and C=N stretch), halogens (C–X stretch and X–C=O stretch), and sulfur compounds.

Dielectric Constants of Materials (In Alphabetical Order)

This chapter presents a list of dielectric constants of different materials in alphabetical order.

Short-Wave Near-Infrared Spectroscopy

This chapter discusses short-wave and near-infrared (NIR) spectroscopy. It explores the issues relative to a proposed starting wavelength for the NIR spectral region. The usual designation for the visible region includes 380–780 nm. The current official position defines the NIR region extending from 780 nm (12,800 cm -1 ) to 2,500 nm (4,000 cm -1 ), as specified by IUPAC. It may be more appropriate to extend the NIR region to near 695 nm (14,388 cm -1 ), and there is historical and experimental precedent for this claim. To give historical background on the reasoning behind this suggestion, a brief review of pertinent literature is presented in this chapter as a preface to the experimental section. Current instrumentation provides high quality measurements of hydrocarbons with measurement pathlengths of 10 cm or more. The region that is considered the visible spectral region, often designated as a measurement region for electronic transitions, also contains vibrational information. The vibrational information that occurs primarily as the fourth overtone for C–H stretching is described in this chapter.

UV-VIS Spectroscopy Charts

The majority of organic compounds are somewhat transparent in the ultraviolet and visible regions. In some cases, specific types of organic materials absorb ultraviolet (UV) and visible (Vis) radiation, giving useful information toward quantitative analysis or identification of compounds. When combined with physical data such as melting point, solubility, and boiling point, identification can be enhanced using ultraviolet and visible spectroscopy. When UV–Vis spectra are combined with infrared or nuclear magnetic resonance (NMR) spectral data, important structural features can be assessed. UV spectra at lowered temperatures can yield significant increases in structure because of lowered collisional and rotational energy. Large molecules at room temperature can exhibit fine structure in the ultraviolet due to their high rotational energy levels. Solvent interaction is another important characteristic of ultraviolet and visible spectra. The solvent selected needs to be “invisible” in the spectral region of interest as much as is possible. Solvents can have an effect on the position, intensity, and bandwidth of the various absorption bands for any UV–Vis absorbing solute.

Review of Chemometrics Applied to Spectroscopy: Data Preprocessing

This chapter summarizes the articles published in the recent literature pertaining to data-preprocessing methods and data transformations. In general, data transformations are applied to each sample, and each sample is transformed similarly whether a single sample or group of samples is transformed. Preprocessing methods alter each sample according to the characteristics of the entire data set, that is, mean centering or autoscaling. Adding or subtracting a single sample from the data set affects the preprocessing of each sample. In addition, pretreatment methods may refer either to preprocessing methods or data transformations. Articles gathered in this chapter break down into two different areas: data pretreatment used (1) prior to exploratory and classification methods that use only spectral or perhaps class information and (2) prior to calibration that involves predicting some quantity of a future unknown sample based on a measured spectral value.

NIR Band Assignments for Organic Compounds, Polymers, and Rubbers

This chapter presents the C–H, N–H, and O–H stretch absorption bands for specific long wavelength near-infrared NIR (1100–2500 nm) functional groups (1 st to 4 th overtones). It then illustrates a correlation chart for organic compounds and materials. Finally, it tabulates the correlation between polymer materials.

Functional Groupings and Calculated Locations in Nanometers (NM) For NIR Spectroscopy

This chapter lists various functional groups for near-infrared (NIR) spectroscopy, their molecular structure, relative intensity, 1 st , 2 nd , 3 rd , and 4 th overtone. Functional groups covered include esters, anhydrides, acyl halides, and amides.