Near infrared spectra of some cobalt(II) compounds

1968 ◽  
Vol 21 (7) ◽  
pp. 1775
Author(s):  
DP Graddon ◽  
GM Mockler
Keyword(s):  
Absorption Band ◽  
Absorption Spectra ◽  
Metal Atom ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Infrared Region ◽  
Absorption Bands ◽  
Heterocyclic Base ◽  
Near Infrared Spectra ◽  
Near Infrared Region

Absorption spectra of compounds CoX2B2 and CoX2B4 (X = Cl, Br, I, or NCS; B = a heterocyclic base) have been obtained by reflectance and in solution in the near infrared region between 1000 and 2000 mμ. The spectra are characteristic of the stereochemistry of the metal atom: octahedral compounds have a single absorption band near 1100 mμ, e < 10; tetrahedral compounds have three overlapping absorption bands near 1100,1400, and 1700 mp, 30 < < 150. Comparisons are made with previously observed spectra of octahedral and tetrahedral species of the types CoL2+6 and CoX2-4.

scholarly journals Near Infrared Spectra of Southern Be Stars

1987 ◽  
Vol 92 ◽  
pp. 239-241
Author(s):  
L. Pastori
Keyword(s):  
Infrared Spectra ◽  
Spectral Type ◽  
Near Infrared ◽  
Infrared Region ◽  
Bright Star ◽  
Be Stars ◽  
Star Catalogue ◽  
Near Infrared Spectra ◽  
Near Infrared Region ◽  
Right Ascension

Spectra of northern Be stars in the near infrared region have been already described by some authors (see Slettebak, 1979 for a brief review). This paper presents general results for southern Be stars obtained from more than 100 spectrograms in the region λλ7750-9000 Å the spectra were taken in four nights of February 1985 at the 1.5m ESO telescope with the reticon instrumentation; the dispersion is 58 Åmm-1. All the available southern Be stars (right ascension between 4h and 17h) listed in the Bright Star Catalogue (Hoffleit and Jaschek, 1982) were observed. Table 1 lists the number of stars vs. spectral type (columns 1 and 2) and the number of stars which display emission at the Paschen series, 0I λ8446 Å and Call triplet (columns 3 to 5).

Harmonic and Anharmonic Oscillator Models for Pure Vibrational Infrared Spectroscopy of Diatomic Molecules

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Rohit Singh
Keyword(s):  
Infrared Spectroscopy ◽  
Harmonic Oscillator ◽  
Absorption Spectra ◽  
Near Infrared ◽  
Anharmonic Oscillator ◽  
Diatomic Molecules ◽  
Infrared Region ◽  
Molecular Vibration ◽  
Absorption Bands ◽  
Near Infrared Region

In molecular vibrational infrared spectroscopy, absorption spectra arise from molecular vibration and correspond to transitions between the vibrational energy levels associated with a given electronic state of the molecule. The vibrational transitions, which fall in the near infrared region, are induced through the interaction of the molecular electric dipole with the electric vector of the electromagnetic radiation. The near infrared region extends roughly from 1?m to ?10?^2 ?m. The article explains the pure vibrational absorption spectra of diatomic molecules such as HCl, HBr, HI, CO, … etc. In order to explain the vibrational spectra, diatomic molecules are treated as harmonic oscillator and anharmonic oscillator. In the harmonic oscillator model, we get only one absorption band at the wavenumber value? ?_osc corresponding to frequency of oscillation?_osc while in the actual experimental data, there are many absorption bands corresponding to wave numbers slightly lesser than ? ?_osc, 2? ?_osc, 3? ?_osc, ……..The occurrence of these additional bandsis attributed to the selection rule ?v=±2, ±3, ±4, ……The additional bands are having lesser intensity and are called overtone bands.

Mid and near Infrared Study of Carbohydrates by Canonical Correlation Analysis

1993 ◽  
Vol 1 (2) ◽  
pp. 99-108 ◽  
Author(s):  
P. Robert ◽  
M.F. Devaux ◽  
A. Qannari ◽  
M. Safar
Keyword(s):  
Correlation Analysis ◽  
Infrared Spectra ◽  
Canonical Correlation ◽  
Near Infrared ◽  
Sugar Content ◽  
Infrared Region ◽  
Total Sugar ◽  
Mid Infrared ◽  
Total Sugar Content ◽  
Near Infrared Spectra

Multivariate data treatments were applied to mid and near infrared spectra of glucose, fructose and sucrose solutions in order to specify near infrared frequencies that characterise each carbohydrate. As a first step, the mid and near infrared regions were separately studied by performing Principal Component Analyses. While glucose, fructose and sucrose could be clearly identified on the similarity maps derived from the mid infrared spectra, only the total sugar content of the solutions was observed when using the near infrared region. Characteristic wavelengths of the total sugar content were found at 2118, 2270 and 2324 nm. In a second step, the mid and near infrared regions were jointly studied by a Canonical Correlation Analysis. As the assignments of frequencies are generally well known in the mid infrared region, it should be useful to study the relationships between the two infrared regions. Thus, the canonical patterns obtained from the near infrared spectra revealed wavelengths that characterised each carbohydrate. The OH and CH combination bands were observed at: 2088 and 2332 nm for glucose, 2134 and 2252 nm for fructose, 2058 and 2278 nm for sucrose. Although a precise assignment of the near infrared bands to chemical groups within the molecules was not possible, the present work showed that near infrared spectra of carbohydrates presented specific features.

Quantum mechanical simulations of near-infrared spectra of biomolecules – Long-chain fatty acids

NIR news ◽  
2018 ◽  
Vol 29 (6) ◽  
pp. 13-19 ◽  
Author(s):  
Krzysztof B Beć ◽  
Justyna Grabska
Keyword(s):  
Fatty Acids ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Infrared Region ◽  
Quantum Mechanical ◽  
Long Chain Fatty Acids ◽  
Near Infrared Spectra ◽  
Technical Article ◽  
Long Chain ◽  
Chain Fatty Acids

Exact and in-depth interpretation of near-infrared spectra has often appeared problematic in any case stepping beyond the simplest molecules. The inherent complexity of near-infrared spectra due to the abundance of combination modes and the resulting extensive band overlay frequently limits our comprehension of the spectral bands to vague wavenumber regions in which certain modes likely appear. Coincidently, quantum mechanical simulation of spectra which could offer momentous support in solving such problems has rather been rare in the case of near-infrared region due to practical limitations. Recent years have seen a trending development of accurate and affordable methods of near-infrared spectra simulation. A trend in modelling increasingly complex molecules can be noticed reaching even fairly large biomolecules. In this technical article we overview the most recent accomplishments in the field on the example of long-chain fatty acids and their cyclic dimers, which extend beyond 100 atoms.

Spectrophotometry of Human Hemoglobin in the near Infrared Region from 1000 to 2500 nm

1994 ◽  
Vol 2 (2) ◽  
pp. 59-65 ◽  
Author(s):  
J. Todd Kuenstner ◽  
Karl H. Norris
Keyword(s):  
Near Infrared ◽  
Infrared Region ◽  
Second Derivative ◽  
Human Hemoglobin ◽  
Absorption Bands ◽  
Near Infrared Region ◽  
Absorbance Spectra

Absorbance and first and second derivative absorbance spectra and quarter-millimolar absorptivity coefficients for hemoglobin species including oxy-, deoxy-, carboxy- and methemoglobin in the visible and in the near infrared regions from 620 nm to 2500 nm are presented. At wavelengths longer than 1500 nm, the absorbance and second derivative absorbance spectra of hemoglobin species are similar for all of the species. Absorption bands are present centred at 1690, 1740, 2056, 2170, 2290 and 2350 nm.

Surface Plasmon Resonance with Electrospun Nanofibers on Gold Surface

2009 ◽  
Vol 1173 ◽  
Author(s):  
Kazuma Tsuboi ◽  
Hidetoshi Matsumoto ◽  
Mie Minagawa ◽  
Akihiko Tanioka
Keyword(s):  
Surface Plasmon ◽  
Near Infrared ◽  
Polarized Light ◽  
Electrospun Nanofibers ◽  
Gold Surface ◽  
Infrared Region ◽  
Peak Wavelength ◽  
Absorption Bands ◽  
Propagation Length ◽  
Near Infrared Region

AbstractIn this paper we report new excitation method of surface plasmon polariton (SPP) at air/gold interface with electrospun nanofibers. Nanofibers of polyvinylpirrolidone were electrospun onto the surface of a gold film. The observations by scanning electron microscopy and optical microscopy indicated that the average diameters of the nanofibers were about 300 nm and average sizes of pores were about 30-40 μm. Optical response of the nanofibers on gold surface was investigated by polarized reflection absorption spectroscopy (RAS). The RAS spectrum with p-polarized light showed two absorption bands while the spectrum with s-polarized light only one band. One is a band at about 520 nm that also found in the spectrum with s-polarized light. Another is a broad band in the near-infrared region which found only with p-polarized light. The peak intensity of the latter band increases with increase of incident angle of the polarized light and the peak wavelength of the band shifted to longer wavelength. These responses suggested that SPP at air/gold interface was excited with the scattering light from the electrospun nanofibers. We also found that the peak wavelength of the absorption band in near-infrared region changed with the increase of the amount of the nanofibers. This may be due to the fact that the sizes of the pores on gold surface became smaller than the propagation length of SPP, which resulted in scattering and interference of SPP.

scholarly journals Recent advances in modeling vibrational spectra of food adulterants – Theoretical simulation of IR and NIR bands of melamine

NIR news ◽  
2019 ◽  
Vol 30 (4) ◽  
pp. 5-10
Author(s):  
Krzysztof B Beć
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared ◽  
Infrared Region ◽  
Spectral Information ◽  
Complex Data ◽  
Theoretical Simulation ◽  
Methods Of Analysis ◽  
Near Infrared Spectra ◽  
Near Infrared Region ◽  
Detection And Quantification

Food safety may be one of the major concerns of the global society in the forthcoming decades. Analytical vibrational spectroscopy is expected to become a major tool used for controlling the food quality at every stage of its production, storage and delivery. Near-infrared and infrared spectroscopy have rapidly been evolving in analytical applications over the last decades with strong hyphenation to numerical and statistical methods of analysis of complex data, which are known as chemometrics. Analytical spectroscopy has reached a remarkable value for both industrial and institutional laboratories nowadays. However, the routinely used methods of analysis do not attempt to interpret the analysed spectral information in physicochemical sense. Therefore, analytical routines seldom take advantage of the molecular background underlying the properties of analysed sample. In the present article, we review the most recent accomplishments that evidence the progress which may be achieved when that background becomes actually available. We focus on the example of infrared and near-infrared spectra simulation applied to melamine, one of the most infamous food adulterant. This sheds light on the correspondences between infrared and near-infrared region observed earlier in the analytical papers dealing with detection and quantification of melamine in food products.

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