Showing papers on "Fourier transform spectroscopy published in 1972"
299 citations
Book•
01 Jan 1972
TL;DR: In this article, Boudreaux et al. compared and analyzed the properties of isolated pyrimidine bases and measured the effect of various parameters on their properties, such as vibrational line profiles and frequency shifts.
Abstract: 1. Applications of Matrix Infrared Spectroscopy to Mapping of Bimolecular Reaction Paths (H. Frei). Introduction. Oxygen Transfer Reactions. Hydrogen Transfer Reactions. Concluding Remarks. 2. Vibrational Line Profile and Frequency Shift Studies by Raman Spectroscopy (B.P. Asthana, W. Kiefer). Introduction. Deconvolution of Raman Line Profile. Determination of Frequency Shifts by Raman Difference Spectroscopy (RDS). Study of Linewidth Changes by RDS. Experimental Techniques. Applications. Summary. 3. Microwave Fourier Transform Spectroscopy (A. Bauder). Introduction. Experimental. Rotational Spectra. 4. Ab Initio Quality of SCMEH-MO Calculations of Complex Inorganic Systems (E.A. Boudreaux). Introduction. Theoretical Foundation. Applications and Results. Comments, Conclusions and Acknowledgments. 5. Calculated and Experimental Vibrational Spectra and Force Fields of Isolated Pyrimidine Bases (W.B. Person, K. Szczepaniak). Introduction. Methods for Study of Isolated Molecules. Stabilities, Structures, and Dipole Moments of Isolated Pyrimidine Bases. Comparison of Experimental and Calculated Infrared Spectra for Pyrimidine Bases. Basis Set Dependence of Calculated Infrared Spectra and Vibrational Parameters for Uracil. Comparison of Spectra Calculated for Uracil, Thymine, Cytosine, and 1-Methylcytosine. Comparison and Transferability of Bond Force Constants from Thymine, Uracil, Cytosine, and 1-Methylcytosine. Comparison and Transferability of Bond Dipole Derivatives from Uracil, Thymine, Cytosine, and 1-Methylcytosine. Concluding Remarks. Author Index. Subject Index.
193 citations
TL;DR: In this article, the Fourier transform technique was used to obtain high resolution spectra and/or relaxation of chemically shifted nuclei under these extreme conditions, at pressures up to 5 kilobar and temperatures from −50 to 350°C.
Abstract: Instrumentation for the measurement of spin lattice relaxation times in liquids at pressures up to 5 kilobar and temperatures from −50 to 350°C is described. The experimental setup allows the use of the Fourier transform technique to obtain high resolution spectra and/or relaxation of chemically shifted nuclei under these extreme conditions.
93 citations
TL;DR: The Driven Equilibrium Fourier Transform (DEFT) technique for signal enhancement in pulsed 13C magnetic resonance spectroscopy has been investigated for several small 60-enriched molecules.
54 citations
52 citations
TL;DR: The application of IR interferometry or of NMR pulse methods, followed by Fourier transformation of the resultant interferogram, permits acquisition of spectral data in a time that is orders of magnitude less than by conventional spectroscopic methods.
Abstract: The recent introduction of Fourier transform methods is revolutionizing IR and NMR spectroscopy. The application of IR interferometry or of NMR pulse methods, followed by Fourier transformation of the resultant interferogram, permits acquisition of spectral data in a time that is orders of magnitude less than by conventional spectroscopic methods. This reduction in time permits the study of transient species, or by "time-averaging" procedures S/N may be improved without the expenditure of inordinate amounts of time. The FT methods finds especially important application in the study of NMR spectra of nuclei of low sensitivity and low abundance, such as (13)C.
52 citations
01 Jan 1972
48 citations
46 citations
TL;DR: The characteristic asorption, reflection, or emission of particu lar frequencies of IR radiation has been used extensively over the last two decades to identify compounds and mixtures and to investigate intermolecular and intramolecular interactions as mentioned in this paper.
Abstract: The characteristic asorption, reflection, or emission of particu lar frequencies of IR radiation has been used extensively over the last two decades to identify compounds and mixtures and to investigate intermolecular and intramolecular interactions. It is probably true to say that IR spectroscopy is the most widely used instrumental technique in analytical chemistry today. This is due to a variety of reasons, including the ease of operation of many IR spectrometers, the ease in which a sample may be classified according to its chemical class from its IR spectrum, the variety of states in which a compound may be investigated, the availability of libraries of IR spectra for the unique identification of a sample, and the accuracy to which quantitative analysis may be carried out.
TL;DR: In this article, the application of the fast Fourier transform (FFT) algorithm to calculating one-dimensional and bi-dimensional (temporal and spatial), power and cross-power (coherence and phase) spectra is examined for solar photospheric fluctuations.
Abstract: The application of the fast-Fourier-transform (FFT) algorithm to calculating one-dimensional and bi-dimensional (temporal and spatial), power and cross-power (coherence and phase) spectra is examined for solar photospheric fluctuations. Alternative methods for smoothing raw spectra, direct averaging (employing various weights) and indirect truncation of the correlation function, are compared, and indirect smoothing is compared with spectra calculated by mean-lagged-product (MLP) methods. Besides providing the raw spectrum, FFT techniques easily allow computing a series of spectra with varying amounts of smoothing. From these spectra a range of satisfactory compromise between resolution and stability can be determined which helps in the interpretation of spectral trends, and in identifying more clearly the existence and significance of spectral features. For bi-dimensional spectra presented as contour plots, this range of satisfactory smoothing can be restricted, particularly when spectral trends must be represented by small-scale contours. Equivalent spectra (i.e. comparable equivalent degrees of freedom) computed or smoothed by different methods have minor, but not negligible, differences. Examination of these differences favors computing of FFT spectra smoothed by averaging for photospheric fluctuations.
TL;DR: The measurement of naturally occurring or induced circular or linear dichroism is extremely useful in the elucidation of structural problems or the investigation of the spectroscopic or magnetic properties of inorganic or solid state materials.
Abstract: The measurement of naturally occurring or induced circular or linear dichroism is extremely useful in the elucidation of structural problems or the investigation of the spectroscopic or magnetic properties of inorganic or solid state materials. The accurate study of very small phenomena (viz., 10–10 optical density units) requires the use of differential techniques whereas the direct measurement with polarized light is applicable to large signals such as those encountered for, e.g., ferromagnetic crystals.
TL;DR: Development of the arc-stabilized mercury lamp, adequate stabilization of the cooled detector, and selection of optimum sampling time have provided reproducible and high S/N interferograms of this Michelson-type Fourier spectrometer.
Abstract: This paper describes the construction, performance, and applications of a Michelson-type Fourier spectrometer designed for spectroscopy in the 10-cm−1 to 200-cm−1 spectral region. Development of the arc-stabilized mercury lamp, adequate stabilization of the cooled detector, and selection of optimum sampling time have provided reproducible and high S/N interferograms. The evaluated reproducibility and accuracy of intensity of the spectrometer are better than :±2%. An apodized resolution of 0.1 cm−1 and accuracy of frequency within 0.015 cm−1 have also been obtained. The electron spin resonance of some biological substances and the refractive index of solids, for example, have been measured with this spectrometer.
TL;DR: In this article, a procedure for converting the Varian XL-100 NMR spectrometer from continuous wave to Fourier transform operation is described, permitting the use of many different kinds of computer systems and pulse amplifiers.
Abstract: A procedure is described for converting the Varian XL‐100 NMR spectrometer from continuous wave to Fourier transform operation. The modification is relatively simple, permitting the use of many different kinds of computer systems and pulse amplifiers. Selection of either the continuous wave or Fourier transform mode is straight‐forward in the modified spectrometer.
TL;DR: High resolution spectra obtained with a PEPSIOS spectrometer using the entire disk of Jupiter, a rapidly rotating planet, are presented as an example.
Abstract: The Doppler shift of light from a rapidly rotating or rapidly flowing source limits the spectroscopic resolution with which it can be studied using Fabry-Perot spectrometers that have the usual axial fringe adjustment. Because of the angular dependence of the wavenumber transmitted by the Fabry-Perot, the entrance aperture can be positioned off-axis at an angle chosen such that the wavenumber shift across the entrance aperture matches the shift presented by the source, thereby compensating for the Doppler effect. The principle can be extended to the Michelson interferometer for Fourier transform spectroscopy when the Michelson is used without field compensation. High resolution spectra obtained with a PEPSIOS spectrometer using the entire disk of Jupiter, a rapidly rotating planet, are presented as an example.
TL;DR: It is demonstrated that 'H Fourier transform spectroscopy can be successfully carried out on deuterated compounds containing a small, unnatural abundance of 'H.
Abstract: The application of nuclear magnetic resonance spectroscopy to biopolymers and other complicated compounds of biological importance is considerably aided by the use of compounds of unusual isotopic composition that can be obtained by biosynthesis. Isotope hybrid proteins that are basically fully deuterated but which contain 'H at known sites in the molecule greatly simplify the interpretation of high resolution nmr data. Fully deuterated chiorophylls and an unusual isotope hybrid chlorophyll 2H-chlorophyll a ['H-(CH,)l 11 in which only the methyl group in the carbomethoxy group contains ordinary 'H have particular utility in chlorophyll aggregation studies by nmr. Finally, it is demonstrated that 'H Fourier transform spectroscopy can be successfully carried out on deuterated compounds containing a small, unnatural abundance of 'H.
TL;DR: In this article, a brief review of the nuclear relaxation phenomenon, sensitivity enhancement using the pulse technique, pulse instrumentation, and analytical applications of pulse Fourier transform NMR are discussed.
Abstract: Recent advances in NMR spectroscopy allow one to study extremely dilute systems or nuclei which occur in low natural abundance and/or have poor sensitivity for NMR detection. This paper describes various pulse and pulse Fourier transform NMR techniques. Included in this introduction are: (1) a brief review of the nuclear relaxation phenomenon, (2) sensitivity enhancement using the pulse technique, (3) pulse instrumentation, and (4) the analytical applications of pulse Fourier transform NMR.
TL;DR: A real-time Fourier computer has been designed and tested as part of the Lunar and Planetary Laboratory's program of airborne infrared astronomy using Fourier spectroscopy.
Abstract: A real-time Fourier computer has been designed and tested as part of the Lunar and Planetary Laboratory's program of airborne infrared astronomy using Fourier spectroscopy. The value and versatility of this device are demonstrated with specific examples of laboratory and in-flight applications.
Book•
01 Jan 1972
TL;DR: One day, you will discover a new adventure and knowledge by spending more money as discussed by the authors. But when? Do you think that you need to obtain those all requirements when having much money? Why don't you try to get something simple at first? That's something that will lead you to know more about the world, adventure, some places, history, entertainment and more?
Abstract: One day, you will discover a new adventure and knowledge by spending more money. But when? Do you think that you need to obtain those all requirements when having much money? Why don't you try to get something simple at first? That's something that will lead you to know more about the world, adventure, some places, history, entertainment, and more? It is your own time to continue reading habit. One of the books you can enjoy now is techniques of high resolution nuclear magnetic resonance spectroscopy here.
TL;DR: In this article, a pulsed nuclear double resonance technique was used for the measurement of high resolution spectra of dilute spins in solids, which used the spin system to perform an analogue Fourier transform and achieved a resolved doublet with a splitting of (36 + or 5) Hz or (9.5+ or 1.3) ppm and a residual linewidth of about 20 Hz.
Abstract: A method is described for the measurement of high resolution spectra of dilute spins in solids. It is a pulsed nuclear double resonance technique which uses the spin system to perform an analogue Fourier transform. Results on the 1.108% abundant 13C resonance in solid adamantane (C10H16) show a resolved doublet with a splitting of (36+or-5) Hz or (9.5+or-1.3) ppm and a residual linewidth of about 20 Hz.
TL;DR: In this article, a simple method is described that enables the recording of a high resolution spectroscopic hologram on low resolution photographic film, where the high spatial frequency of the original spectroscopy hologram is mixed with a lower frequency.
TL;DR: In this article, the use of the Michelson interferometer as a Fourier transform spectrometer was described, and the Fourier transforms of the visibility curves were taken with the aid of a digital computer.
Abstract: The use of the Michelson interferometer as a Fourier transform spectrometer is described. Fringe visibility curves are obtained with an electron photomultiplier or silicon photocell, and Fourier transforms of the visibility curves are taken with the aid of a digital computer. Application of the technique is made to the axial mode structure and phenomenon of “hole burning” in He-Ne lasers, to the shape of the mercury green line and sodium yellow lines, and to the Zeeman spectrum of the mercury green line Δmj = 0 transitions.