Effect of the intramolecular interaction of atomic groups through an intermediate link on the IR absorption band intensity in nitroaromatic compounds

1993 ◽  
Vol 58 (5-6) ◽  
pp. 331-336
Author(s):  
N. B. Lopatina ◽  
P. P. Shorygin ◽  
B. V. Lopatin ◽  
F. S. Mikhailitsyn ◽  
T. E. Gorodilova
Keyword(s):  
Absorption Band ◽  
Intramolecular Interaction ◽  
Nitroaromatic Compounds ◽  
Band Intensity ◽  
Ir Absorption ◽  
Absorption Band Intensity

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.

scholarly journals Absorption and Emission Spectra for C60 Anions

1994 ◽  
Vol 14 (1-3) ◽  
pp. 155-160 ◽  
Author(s):  
Tatsuhisa Kato
Keyword(s):  
Absorption Spectrum ◽  
Absorption Band ◽  
Theoretical Analysis ◽  
Room Temperature ◽  
Emission Spectra ◽  
Mirror Image ◽  
Ir Absorption ◽  
Near Ir ◽  
Laser Experiments ◽  
Ir Bands

Absorption spectra are detected for C60− and C602− produced electrolytically in solution at room temperature. Theoretical analysis of the spectrum of C60− by CNDO/S calculations gives an interpretation of the characteristic near-IR bands, the weak visible bands, and the strong bands in the UV region. The emission spectrum of C60− is a mirror image of the near-IR absorption band, and the detection of the emission reconfirms our original assignment of the absorption spectrum. The nature of the spectrum of C602− is characterized by a similar orbital picture to that of C60−. Further laser experiments of significance are proposed.

scholarly journals Local vibrational modes of vacancy-oxygen-related complexes at room temperature

2020 ◽  
Vol 56 (4) ◽  
pp. 480-487
Author(s):  
E. A. Tolkacheva ◽  
V. P. Markevich ◽  
L. I. Murin
Keyword(s):  
Absorption Band ◽  
Room Temperature ◽  
Clear Correlation ◽  
Ir Absorption ◽  
Oxygen Impurity ◽  
Interstitial Oxygen ◽  
Vibrational Modes ◽  
Oxygen Defect ◽  
Absorption Bands ◽  
Local Vibrational Modes

The isotopic content of natural silicon (28Si (92.23 %), 29Si (4.68 %) и 30Si (3.09 %)) affects noticeably the shape of IR absorption bands related to the oxygen impurity atoms. In the present work an attempt is undertaken to determine the positions of local vibrational modes (LVMs), related to quasimolecules 28Si16OS29Si and 28Si16OS30Si (OS – substitutional oxygen atom), for the absorption spectra measured at room temperature. An estimation of the isotopic shifts of corresponding modes is done by fitting the shape of the experimentally measured absorption band related to the vacancy–oxygen center in irradiated Si crystals. The LVM isotope shifts are found to be equal 2,2 ± 0.25 cm–1 for 28Si-16OS29Si and 4,3 ± 0,9 см–1 for 28Si-16OS30Si in relation to the basic band due to 28Si-16OS28Si, and the full width at half maximum of the A-center absorption band (28Si-16OS28Si) is 5,3 ± 0.25 cm–1. By means of infrared absorption spectroscopy a clear correlation between the disappearance of the divacancy (V2) in the temperature range 200–275 ºС and appearance of two absorption bands with their maxima at 825.8 and 839.2 cm–1 in irradiated oxygen-rich Si crystals is found. The band positioned at 825.8 cm–1 is assigned to a divacancy-oxygen defect V2O formed via an interaction of mobile V2 with interstitial oxygen (Oi ) atoms. The 839.2 cm–1 band is much more pronounced in neutron irradiated samples as compared to samples irradiated with electrons. We argue that it is related to a trivacancy–oxygen defect (V3O) formed via an interaction of mobile V3 with Oi atoms.

Estimation of the infrared absorption of ZnCl2–KBr glass by molecular dynamics

1987 ◽  
Vol 2 (3) ◽  
pp. 357-360 ◽  
Author(s):  
Satoru Inoue ◽  
Mitsuru Tamaki ◽  
Hiroshi Kawazoe ◽  
Masayuki Yamane
Keyword(s):  
Molecular Dynamics ◽  
Absorption Band ◽  
Molecular Dynamic ◽  
Infrared Absorption ◽  
Experimental Results ◽  
Ir Absorption ◽  
Weak Absorption ◽  
Weak Absorption Band ◽  
Oxygen Impurities ◽  
Free Glass

Molecular dynamic calculations have been made on glasses in the ZnCl2–KBr system in order to estimate the infrared (IR) absorption of these glasses. Oxygen-free glass was estimated to be transparent up to 25 μm. Glasses containing oxygen impurities were estimated to be transparent only up to 16 μm, with a weak absorption band around 10.4 μm. This agrees with experimental results of glasses in the ZnCl2–KBr–PbBr2 system.

Observation of a near-IR absorption band of the fluorene excimer by photodissociation spectroscopy

1993 ◽  
Vol 97 (45) ◽  
pp. 11635-11638 ◽  
Author(s):  
Sheng Sun ◽  
Hiroyuki Saigusa ◽  
Edward C. Lim
Keyword(s):  
Absorption Band ◽  
Ir Absorption ◽  
Near Ir
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