Infrared Intensities of Liquids X: Accuracy of Current Methods of Obtaining Optical Constants from Multiple Attenuated Total Reflection Measurements Using the CIRCLE Cell

1992 ◽  
Vol 46 (11) ◽  
pp. 1660-1665 ◽  
Author(s):  
John E. Bertie ◽  
Shuliang L. Zhang ◽  
Rizwan Manji
Keyword(s):  
Acetic Acid ◽  
Optical Constants ◽  
Glacial Acetic Acid ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Refractive Indices ◽  
Pure Liquid ◽  
Multiple Reflections ◽  
The Real ◽  
Infrared Intensities

The literature description of the Bertie-Eysel method for obtaining the optical constants (i.e., the real and imaginary refractive indices) of liquids from multiple attenuated total reflection measurements using the CIRCLE cell is brought up to date in this paper. The accuracy of the computation methods is explored by analyzing pATR spectra which are themselves calculated from known k(ν˜) spectra that contain single Lorentzian bands, and the corresponding known n(ν˜) spectra, and also from simulated, known, n(ν˜) and k(ν˜) spectra of pure liquid methanol and glacial acetic acid. The optical constants are recovered from the pATR spectra and compared with the known originals. It is shown that k(ν˜) spectra that contain k(ν˜) values up to 0.8, 0.7, and 0.6 can be obtained accurately when the real refractive indices are near 1.3, 1.4, and 1.5, respectively. The method is, thus, reliable for spectra that can be accurately measured from the multiple reflections in the CIRCLE cell. It is likely to be troublesome for higher values of the real and the imaginary refractive indices. However, these are best measured by single-reflection methods, and more direct ways of computing the optical constants are available for such methods.

Infrared Intensities of Liquids XIV: Accurate Optical Constants and Molar Absorption Coefficients between 4800 and 450 cm−1 of Chlorobenzene at 25°C from Spectra Recorded in Several Laboratories

1994 ◽  
Vol 48 (1) ◽  
pp. 144-159 ◽  
Author(s):  
John E. Bertie ◽  
R. Norman Jones ◽  
Yoram Apelblat
Keyword(s):  
Refractive Index ◽  
Absorption Coefficient ◽  
Optical Constants ◽  
Absorption Index ◽  
Molar Absorption Coefficient ◽  
Refractive Indices ◽  
The Real ◽  
Infrared Intensities ◽  
Refractive Index Spectrum ◽  
Liquid Chlorobenzene

Accurate infrared absorption intensities of liquid chlorobenzene at 25°C are presented. Their accuracy was estimated from the agreement between the intensities measured by different spectroscopists using different instruments in different laboratories and by different spectroscopists using the same instrument in the same laboratory. The spectra from different spectroscopists have been averaged, unweighted, to give intensity spectra of chlorobenzene that are presented as the best available. The results are presented as graphs and tables of the molar absorption coefficient, Em (ν˜), and the real and imaginary refractive indices, n(ν˜) and k(ν˜), between 4800 and 450 cm−1. The peak heights and the areas under the bands in the absorption index (imaginary refractive index) spectrum are reported, as are areas under the molar absorption coefficient spectrum. Absorption index, k(ν˜), and molar absorption coefficient, Em (ν˜), values are believed accurate to an average ±2.4% at the peaks of bands with kmax > 0.002 and ±3.3% at the peaks of bands with kmax < 0.002. In the baseline k(ν˜) is accurate to ∼ ±5% above 3000 cm−1 and ∼ ±2.5% below 3000 cm−1. The areas under bands in k(ν˜) and Em (ν˜) spectra for which kmax > 0.002 are accurate to ±1.3% on average. The real refractive index, n(ν˜), values are believed to be accurate to ±0.2%.

Infrared Intensities of Liquids XI: Infrared Refractive Indices from 8000 to 2 cm−1, Absolute Integrated Intensities, and Dipole Moment Derivatives of Methanol at 25°C

1993 ◽  
Vol 47 (8) ◽  
pp. 1100-1114 ◽  
Author(s):  
John E. Bertie ◽  
Shuliang L. Zhang ◽  
Hans H. Eysel ◽  
Shipra Baluja ◽  
M. Khalique Ahmed
Keyword(s):  
Refractive Index ◽  
Dipole Moment ◽  
Attenuated Total Reflection ◽  
Refractive Indices ◽  
The Real ◽  
Molar Polarizability ◽  
Infrared Intensities ◽  
Integrated Intensities ◽  
Real Refractive Index ◽  
Better Than

This paper reports infrared absorption intensities of liquid methanol at 25°C between 8000 and 2 cm−1. Measurements were made by attenuated total reflection spectroscopy by four different workers between 1984 and 1991, with the use of CIRCLE cells of two different lengths and with several different alignments of the cell in the instrument. Steps were taken to ensure that as few parameters as possible remained unchanged throughout the series of measurements, to try to reveal systematic errors. The reproducibility was better than ±2.5% in regions of significant absorption. In order to allow comparison between different methods, results of all methods were converted to real and imaginary refractive index spectra. Measurements were also made by transmission spectroscopy in regions of weak absorption, with results that agreed excellently with those from ATR. The ATR and transmission results were combined to give a spectrum between 7500 and 350 cm−1. This spectrum agreed excellently with literature results from 350 to 2 cm−1, and the two sets of measurements were combined to yield a spectrum from 7500 to 2 cm−1. The imaginary refractive index was arbitrarily set to zero between 7500 and 8000 cm−1, where it is always less than 2 × 10−6, in order that the real refractive index can be calculated below 8000 cm−1 by Kramers-Kronig transform. The results are reported as graphs and as tables of the real and imaginary refractive indices between 8000 and 2 cm−1, from which all other infrared properties of liquid methanol can be calculated. The accuracy is estimated to be ±3% below 5000 cm−1 and ±10% above 5000 cm−1 for the imaginary refractive index and better than ±0.5% for the real refractive index. To obtain molecular information from the measurements, one calculates the imaginary molar polarizability spectrum, [Formula: see text] vs. [Formula: see text], under the Lorentz local field assumption, and the area under [Formula: see text] bands is separated into contributions from different vibrations under several approximations. Much accuracy is lost in this process. The changes of the dipole moment during normal vibrations, and during OH, CH, and CO bond stretching and COH torsional motion, are presented.

Vibrational Intensities. XIII. Reduction of Attenuated Total Reflection Data to Optical Constants

1966 ◽  
Vol 70 (5) ◽  
pp. 1525-1535 ◽  
Author(s):  
A. C. Gilby ◽  
John Burr ◽  
William Krueger ◽  
Bryce Crawford
Keyword(s):  
Optical Constants ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Reflection Data

scholarly journals Electrospray Film Deposition for Solvent-Elimination Infrared Spectroscopy

2019 ◽  
Vol 73 (6) ◽  
pp. 638-652
Author(s):  
Andrea Arangio ◽  
Christophe Delval ◽  
Giulia Ruggeri ◽  
Nikunj Dudani ◽  
Amir Yazdani ◽  
...  
Keyword(s):  
Inorganic Compounds ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Film Deposition ◽  
Multiple Reflections ◽  
Solution Composition ◽  
Upper Limit ◽  
Volatile Organic ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

The application of electrospray (ES) for quantitative transfer of analytes from solution to an internal reflection element for analysis by attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy has been developed in this work. The ES ATR FT-IR method is evaluated with non-volatile and semi-volatile organic and inorganic compounds dissolved in pure organic solvents or organics in a mixture with water. The technique demonstrates the capability for rapid solvent evaporation from dilute solutions, facilitating the creation of thin films that allow ATR FT-IR to generate transmission-mode-like spectra. Electrospray ATR FT-IR with multiple reflections displays a linear response ( R2 = 0.95–0.99) in absorbance with the deposited mass and instrumental detection limit < 100 ng, which demonstrates potential for quantitative applications. The method is applicable when crystalline substances are present, even though the formation of particles restricts the upper limit of mass loadings relative to substances forming homogeneous films. In addition to the solvent, semi-volatile compounds can evaporate during the ES process; the magnitude of losses will depend on solution composition and temperature.

scholarly journals Pcl/Chitosan Blended Nanofibrous Tubes Made by Dual Syringe Electrospinning

2015 ◽  
Vol 15 (1) ◽  
Author(s):  
Martin Hild ◽  
Mohammed Fayez Al Rez ◽  
Dilbar Aibibu ◽  
Georgios Toskas ◽  
Tong Cheng ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Cell Culture ◽  
Tensile Testing ◽  
Glacial Acetic Acid ◽  
Vascular Grafts ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Promising Candidate ◽  
Culture Studies ◽  
Fibre Formation

Abstract3D tubular scaffolds made from Poly-(Ɛ-caprolactone) (PCL)/chitosan (CS) nanofibres are very promising candidate as vascular grafts in the field of tissue engineering. In this work, the fabrication of PCL/CS-blended nanofibrous tubes with small diameters by electrospinning from separate PCL and CS solutions is studied. The influence of different CS solutions (CS/polyethylene glycol (PEO)/glacial acetic acid (AcOH), CS/trifluoroacetic acid (TFA), CS/ AcOH) on fibre formation and producibility of nanofibrous tubes is investigated. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) is used to verify the presence of CS in the blended samples. Tensile testing and pore size measurements are done to underline the good prerequisites of the fabricated blended PCL/ CS nanofibrous tubes as potential scaffolds for vascular grafts. Tubes fabricated from the combination of PCL and CS dissolved in AcOH possesses properties, which are favourable for future cell culture studies.

scholarly journals Pcl/Chitosan Blended Nanofibrous Tubes Made by Dual Syringe Electrospinning

2015 ◽  
Vol 15 (1) ◽  
pp. 54-59 ◽  
Author(s):  
Martin Hild ◽  
Mohammed Fayez Al Rez ◽  
Dilbar Aibibu ◽  
Georgios Toskas ◽  
Tong Cheng ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Cell Culture ◽  
Tensile Testing ◽  
Glacial Acetic Acid ◽  
Vascular Grafts ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Promising Candidate ◽  
Culture Studies ◽  
Fibre Formation

Abstract 3D tubular scaffolds made from Poly-(Ɛ-caprolactone) (PCL)/chitosan (CS) nanofibres are very promising candidate as vascular grafts in the field of tissue engineering. In this work, the fabrication of PCL/CS-blended nanofibrous tubes with small diameters by electrospinning from separate PCL and CS solutions is studied. The influence of different CS solutions (CS/polyethylene glycol (PEO)/glacial acetic acid (AcOH), CS/trifluoroacetic acid (TFA), CS/ AcOH) on fibre formation and producibility of nanofibrous tubes is investigated. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) is used to verify the presence of CS in the blended samples. Tensile testing and pore size measurements are done to underline the good prerequisites of the fabricated blended PCL/ CS nanofibrous tubes as potential scaffolds for vascular grafts. Tubes fabricated from the combination of PCL and CS dissolved in AcOH possesses properties, which are favourable for future cell culture studies.

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