Infrared spectroscopy

About: Infrared spectroscopy is a research topic. Over the lifetime, 59565 publications have been published within this topic receiving 1511995 citations. The topic is also known as: infrared spectrometry & IR spectroscopy.

Structure Determination of Organic Compounds

Abstract: Summary Tables.- Combination Tables.- C NMR Spectroscopy.- H NMR Spectroscopy.- Heteronuclear NMR Spectroscopy.- IR Spectroscopy.- Mass Spectrometry.- UV/Vis Spectroscopy.

Evaporated Sn‐doped In2O3 films: Basic optical properties and applications to energy‐efficient windows

Abstract: We review work on In2O3:Sn films prepared by reactive e‐beam evaporation of In2O3 with up to 9 mol % SnO2 onto heated glass. These films have excellent spectrally selective properties when the deposition rate is ∼0.2 nm/s, the substrate temperature is ≳150 °C, and the oxygen pressure is ∼5×10−4 Torr. Optimized coatings have crystallite dimensions ≳50 nm and a C‐type rare‐earth oxide structure. We cover electromagnetic properties as recorded by spectrophotometry in the 0.2–50‐μm range, by X‐band microwave reflectance, and by dc electrical measurements. Hall‐effect data are included. An increase of the Sn content is shown to have several important effects: the semiconductor band gap is shifted towards the ultraviolet, the luminous transmittance remains high, the infrared reflectance increases to a high value beyond a certain wavelength which shifts towards the visible, phonon‐induced infrared absorption bands vanish, the microwave reflectance goes up, and the dc resisitivity drops to ∼2×10−4 Ω cm. The corre...

Ultrasensitive Chemical Analysis by Raman Spectroscopy

Abstract: In the Raman effect, incident light is inelastically scattered from a sample and shifted in frequency by the energy of its characteristic molecular vibrations. Since its discovery in 1927, the effect has attracted attention from a basic research point of view as well as a powerful spectroscopic technique with many practical applications. The advent of laser light sources with monochromatic photons at high flux densities was a milestone in the history of Raman spectroscopy and resulted in dramatically improved scattering signals (for a general overview of modern Raman spectroscopy, see refs 1-5). In addition to this so-called spontaneous or incoherent Raman scattering, the development of lasers also opened the field of stimulated or coherent Raman spectroscopies, in which molecular vibrations are coherently excited. Whereas the intensity of spontaneous Raman scattering depends linearly on the number of probed molecules, the coherent Raman signal is proportional to the square of this number (for an overview, see refs 6 and 7). Coherent Raman techniques can provide interesting new opportunities such as vibrational imaging of biological samples,8 but they have not yet advanced the field of ultrasensitive trace detection. Therefore, in the following article, we shall focus on the spontaneous Raman effect, in the following simply called Raman scattering. Today, laser photons over a wide range of frequencies from the near-ultraviolet to the near-infrared region are used in Raman scattering studies, allowing selection of optimum excitation conditions for each sample. By choosing wavelengths which excite appropriate electronic transitions, resonance Raman studies of selected components of a sample or parts of a molecule can be performed.9 In the past few years, the range of excitation wavelengths has been extended to the near-infrared (NIR) region, in which background fluorescence is reduced and photoinduced degradation from the sample is diminished. High-intensity NIR diode lasers are easily available, making this region attractive for compact, low cost Raman instrumentation. Further, the development of low noise, high quantum efficiency multichannel detectors (chargecoupled device (CCD) arrays), combined with highthroughput single-stage spectrographs used in combination with holographic laser rejection filters, has led to high-sensitivity Raman spectrometers (for an overview on state-of-the-art NIR Raman systems, see ref 10). As we shall show in section 2, the nearinfrared region also has special importance for ultrasensitive Raman spectroscopy at the singlemolecule level. As with optical spectroscopy, the Raman effect can be applied noninvasively under ambient conditions in almost every environment. Measuring a Raman spectrum does not require special sample preparation techniques, in contrast with infrared absorption spectroscopy. Optical fiber probes for bringing excitation laser light to the sample and transporting scattered light to the spectrograph enable remote detection of Raman signals. Furthermore, the spatial and temporal resolution of Raman scattering are determined by the spot size and pulse length, respectively, of the excitation laser. By using a confocal microscope, Raman signals from femtoliter volumes (∼1 μm3) can by observed, enabling spatially resolved measurements in chromosomes and cells.11 Techniques such as multichannel Hadamard transform Raman microscopy12,13 or confocal scanning Fourier transform Raman microscopy14 allow generation of high-resolution Raman images of a sample. Recently, Raman spectroscopy was performed using near-field optical microscopy.15-17 Such techniques overcome the diffraction limit and allow volumes significantly smaller than the cube of the wavelength to be investigated. In the time domain, Raman spectra can be measured on the picosecond time scale, providing information on short-lived species such as excited 2957 Chem. Rev. 1999, 99, 2957−2975

Handbook of vibrational spectroscopy

Abstract: VOLUME 1: THEORY AND INSTRUMENTATION Introduction to the Theory and Practice of Vibrational Spectroscopy Instrumentation for Mid- and Far-infrared Spectroscopy Instrumentation for Near-infrared Spectroscopy Instrumentation for Raman Spectroscopy Time-resolved Spectroscopy Dichroism and Optical Activity in Vibrational Spectroscopy Surface-enhanced Vibrational Spectroscopy Other Instrumental Approaches for Vibrational Spectroscopy Calibration Procedures and Standards for Vibrational Spectroscopy VOLUME 2: SAMPLING TECHNIQUES Mid- and Near-infrared Transmission Spectroscopy Mid-infrared External Reflection Spectroscopy Mid-infrared Internal Reflection Spectroscopy Diffuse Reflection Spectroscopy Other IR Sampling Techniques Raman Spectroscopy Low Temperature and High Pressure Sampling Techniques Microscopy Depth profiling by Vibrational Spectroscopy Optical Conduits for Vibrational Specroscopy Hyphenated Techniques Atmospheric VOLUME 3: SAMPLE CHARACTERIZATION AND SPECTRAL DATA PROCESSING Spectra-Structure Correlations Group Theoretical and Numerical Approaches to the Calculation of Vibrational Spectra Discrimant Analysis Two-dimensional (2D) Analysis Spectral Enhancement and Band Resolution Techniques Quantitative Analysis Anomalies, Atifacts and Common Errors in Using Vibrational Spectroscopy Techniques Glossary VOLUME 4: APPLICATIONS IN INDUSTRY, MATERIALS AND THE PHYSICAL SCIENCES Analysis and Characterization of Polymers and Rubbers Rheo-optical Measurements of Polymers and Rubbers Materials Science Spectoelectrochemistry Process Vibrational Spectroscopy Atmospheric and Astronomical Vibrational Spectroscopy Industrial Applications of Vibrational Spectroscopy Forensic Applications of Vibrational Spectroscopy Catalysis Other Applications of Vibrational Spectroscopy Vibrational Spectroscopy in Education VOLUME 5: APPLICATIONS IN LIFE, PHARMACEUTICAL AND NATURAL SCIENCES Biomedical Applications Biochemical Applications Pharmaceutical Applications Food Science Agricultural Applications Abbreviations and Acronyms, Glossary, List of Contributors and Subject Index

Infrared Spectra of Ferrites

Abstract: The infrared spectra of 7 ferrites of the formula $M{\mathrm{Fe}}_{2}{\mathrm{O}}_{4}$, where $M$ designates a divalent metal, are presented and analyzed. Electronic absorption was observed in the visible and near-infrared regions. Two absorption bands arising from interatomic vibrations were measured and force constants calculated for the stretching of bonds between octahedral or tetrahedral metal ions and oxide ions. These force constants are in agreement with the elastic and thermodynamic properties of these compounds and are sensitive to distribution of metal ions between the alternate sites. The integrated vibrational band intensities were measured: they are compatible with predominantly ionic bonding for these structures.