Integrated absorption-band intensity of the valence vibration of the isocyanate group

1972 ◽  
Vol 17 (1) ◽  
pp. 923-925
Author(s):  
N. F. Smirnova ◽  
Yu. I. Mushkin ◽  
A. I. Finkel' Shtein ◽  
B. M. Tsigin
Keyword(s):  
Absorption Band ◽  
Valence Vibration ◽  
Isocyanate Group ◽  
Band Intensity ◽  
Absorption Band Intensity

scholarly journals H 2 O−N 2 collision-induced absorption band intensity in the region of the N 2 fundamental: ab initio investigation of its temperature dependence and comparison with laboratory data

2012 ◽  
Vol 370 (1968) ◽  
pp. 2691-2709 ◽  
Author(s):  
Yu. I. Baranov ◽  
I. A. Buryak ◽  
S. E. Lokshtanov ◽  
V. A. Lukyanchenko ◽  
A. A. Vigasin
Keyword(s):  
Absorption Band ◽  
Ab Initio ◽  
Temperature Dependence ◽  
Laboratory Data ◽  
Basis Set ◽  
Band Intensity ◽  
Intermolecular Potential ◽  
Laboratory Evaluation ◽  
Induced Absorption ◽  
Absorption Band Intensity

The present paper aims at ab initio and laboratory evaluation of the N 2 collision-induced absorption band intensity arising from interactions between N 2 and H 2 O molecules at wavelengths of around 4 μm. Quantum chemical calculations were performed in the space of five intermolecular coordinates and varying N−N bond length using Møller–Plesset perturbation and CCSD(T) methods with extrapolation of the electronic energy to the complete basis set. This made it possible to construct the intermolecular potential energy surface and to define the surface of the N−N dipole derivative with respect to internal coordinate. The intensity of the nitrogen fundamental was then calculated as a function of temperature using classical integration. Experimental spectra were recorded with a BOMEM DA3-002 FTIR spectrometer and 2 m base-length multipass White cell. Measurements were conducted at temperatures of 326, 339, 352 and 363 K. The retrieved water–nitrogen continuum significantly deviates from the MT_CKD model because the relatively strong nitrogen absorption induced by H 2 O was not included in this model. Substantial uncertainties in the measurements of the H 2 O−N 2 continuum meant that quantification of any temperature dependence was not possible. The comparison of the integrated N 2 fundamental band intensity with our theoretical estimates shows reasonably good agreement. Theory indicates that the intensity as a function of temperature has a minimum at approximately 500 K.

Infrared Study of Styrene-4-Methylstyrene Copolymers

1989 ◽  
Vol 43 (3) ◽  
pp. 442-444 ◽  
Author(s):  
R. A. Nyquist ◽  
M. Malanga
Keyword(s):  
Infrared Spectroscopy ◽  
High Temperature ◽  
Quantitative Analysis ◽  
Low Temperature ◽  
Absorption Band ◽  
Weight Percent ◽  
Crystalline Form ◽  
Syndiotactic Polystyrene ◽  
Infrared Study ◽  
Absorption Band Intensity

Two types of crystalline syndiotactic polystyrene units are observed in these styrene- p-methylstyrene copolymers. The low-temperature crystalline form is observed in copolymers containing 2 weight percent or less 4-methylstyrene, and the high-temperature crystalline form is observed in copolymers containing 3 to 7 weight percent 4-methylstyrene. Quantitative analysis of styrene-4-methylstyrene copolymers can be performed with the use of infrared spectroscopy and an infrared absorption band intensity ratio technique.

First Nano-Infrared Spectroscopy and Imaging Measurements of Single Phospholipid Bilayers

2018 ◽  
Author(s):  
Adrian Cernescu ◽  
Michał Szuwarzyński ◽  
Urszula Kwolek ◽  
Karol Wolski ◽  
Paweł Wydro ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Ir Spectroscopy ◽  
Absorption Band ◽  
Spectral Region ◽  
Near Field ◽  
Phospholipid Bilayers ◽  
Model Systems ◽  
Absorption Bands ◽  
Protein Complement ◽  
20 Nm

<div><div>Scattering-mode Scanning Near-Field Optical Microscopy (sSNOM) allows one to obtain absorption spectra in the mid-IR region for samples as small as 20 nm in size. This configuration has made it possible to measure FTIR spectra of the protein complement of membranes. (Amenabar 2013) We now show that mid-IR sSNOM has the sensitivity required to measure spectra of phospholipids in individual bilayers in the spectral range 800 cm<sup>-1</sup>–1400 cm<sup>-1</sup>. We have observed the main absorption bands of the dipalmitoylphosphatidylcholine headgroups in this spectral region above noise level. We have also mapped the phosphate absorption band at 1070 cm<sup>-1</sup> simultaneously with the AFM topography. We have shown that we could achieve sufficient contrast to discriminate between single and multiple phospholipid bilayers and other structures, such as liposomes. This work opens the way to further research that uses nano-IR spectroscopy to describe the biochemistry of cell membranes and model systems.</div></div><div></div>

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