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.

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.

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.

Barcoding without DNA? Species identification using near infrared spectroscopy

Zootaxa ◽  
2011 ◽  
Vol 2933 (1) ◽  
pp. 46 ◽  
Author(s):  
JAIME I. RODRÍGUEZ-FERNÁNDEZ ◽  
CLAUDIO J. B. DE CARVALHO ◽  
CELIO PASQUINI ◽  
KÁSSIO MICHELL GOMES DE LIMA ◽  
MAURICIO O. MOURA ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Dna Barcoding ◽  
Species Identification ◽  
Near Infrared Spectroscopy ◽  
Species Delimitation ◽  
Metabolic Profile ◽  
Near Infrared ◽  
Infrared Region ◽  
Neotropical Region ◽  
Near Infrared Region

Hennig's holomorphology concept defines taxonomy as a process that synthesizes evidence from all relevant comparative sources. One possible source is metabolomics, in which the global metabolic profile is analyzed. An integral metabolic profile can be quickly obtained, nondestructively, through spectroscopy in the near infrared region. Here we use near infrared spectroscopy and chemometry to identify nine species of flies in the genus Neodexiopsis Malloch (Muscidae, Diptera). This genus is the most species-rich of the Muscoidea in the Neotropical region. Identification success demonstrates that near infrared spectroscopy may provide a new source of data to test and organize hypotheses of species delimitation. Comparing near infrared spectroscopy with DNA barcoding, spectroscopy may have even greater conceptual merit as a true barcode of life.

Quantitative analysis of hemoglobin oxygenation state of rat brain in situ by near-infrared spectrophotometry

1988 ◽  
Vol 64 (2) ◽  
pp. 796-802 ◽  
Author(s):  
O. Hazeki ◽  
M. Tamura
Keyword(s):  
Absorption Spectra ◽  
Near Infrared ◽  
Infrared Region ◽  
Hemoglobin Content ◽  
Hemoglobin Oxygenation ◽  
Absorbance Changes ◽  
Near Infrared Region ◽  
The Difference ◽  
Difference Absorption ◽  
The Brain

The light in the near-infrared region (700–900 nm) was illuminated on the rat head, and absorption spectra were measured with the transmitted light under various conditions. The absorbance changes less than 780 nm were attributable to hemoglobin in the brain tissue, whereas those greater than 780 nm were associated with both hemoglobin and cytochrome oxidase. The changes of oxy- and total (oxy- plus deoxy-) hemoglobin content in the rat head could be monitored quantitatively by expressions of delta A700--1.20 delta A730 and delta A700--1.52 delta A730, respectively. The oxyhemoglobin content in the tissue was decreased as the O2 tension in inspired gas was lowered. At 10% O2 approximately 50% of hemoglobin was deoxygenated. The total hemoglobin content was increased under anoxic conditions. Inhalation of 5% CO2 and intravenous injection of a Ca2+ blocker nicardipine increased the O2 saturation of hemoglobin in the brain. These conclusions were confirmed by measuring the difference absorption spectra in the near-infrared region.

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