Infrared intensities of liquids XXII: Optical and dielectric constants, molar polarizabilities, and integrated intensities of liquid benzene-d 6 at 25 °C between 5000 and 450 cm -1

1998 ◽  
Vol 362 (1) ◽  
pp. 91-108 ◽  
Author(s):  
J. E. Bertie ◽  
C. Dale Keefe
Keyword(s):  
Dielectric Constants ◽  
Liquid Benzene ◽  
Infrared Intensities ◽  
Integrated Intensities

Infrared Intensities of Liquids XX: The Intensity of the OH Stretching Band of Liquid Water Revisited, and the Best Current Values of the Optical Constants of H2O(l) at 25°C between 15,000 and 1 cm−1

1996 ◽  
Vol 50 (8) ◽  
pp. 1047-1057 ◽  
Author(s):  
John E. Bertie ◽  
Zhida Lan
Keyword(s):  
Refractive Index ◽  
Liquid Water ◽  
Peak Height ◽  
Dielectric Constants ◽  
The Real ◽  
Infrared Intensities ◽  
Refractive Index Spectrum ◽  
Relative Errors ◽  
Integrated Intensities ◽  
Normal Laboratory

The previously reported nonreproducibility of the intensity of the OH stretching band of liquid water has been explored. It was found that it can be eliminated in measurements with the Circle® multiple ATR cell by ensuring that the ATR rod is coaxial with the glass liquid holder. It was also found that normal laboratory temperature variations of a few degrees change the intensity by ⩽∼1% of the peak height. A new imaginary refractive index spectrum of water has been determined between 4000 and 700 cm1 as the average of spectra calculated from ATR spectra recorded by four workers in our laboratory over the past seven years. It was obtained under experimental and computational conditions superior to those used previously, but is only marginally different from the spectra reported in 1989. In particular, the integrated intensities of the fundamentals are not changed significantly from those reported in 1989. The available imaginary refractive index, k, values between 15,000 and 1 cm−1 have been compared. The values that are judged to be the most reliable have been combined into a recommended k spectrum of H2O(l) at 25 °C between 15,000 and 1 cm−1, from which the real refractive index spectrum has been calculated by Kramers–Kronig transformation. The recommended values of the real and imaginary refractive indices and molar absorption coefficients of liquid water at 25 ± 1 °C are presented in graphs and tables. The real and imaginary dielectric constants and the real and imaginary molar polarizabilities in this wavenumber range can be calculated from the tables. Conservatively estimated probable errors of the recommended k values are given. The precision with which the values can be measured in one laboratory and the relative errors between regions are, of course, far smaller than these probable errors. The recommended k values should be of considerable value as interim standard intensities of liquid water, which will facilitate the transfer of intensities between laboratories.

The Determination of Absolute Infrared Intensities with a Fourier Transform Spectrometer

1979 ◽  
Vol 33 (4) ◽  
pp. 346-348 ◽  
Author(s):  
Kerin Scanlon ◽  
Leo Laux ◽  
John Overend
Keyword(s):  
Fourier Transform ◽  
Test Case ◽  
Program Of Study ◽  
A Value ◽  
Integrated Intensity ◽  
Infrared Intensities ◽  
Vibration Rotation ◽  
Integrated Intensities ◽  
Systematic Program

In principle it is apparent that Fourier transform infrared spectroscopy offers a number of significant advantages in the determination of infrared intensities integrated over the rotational fine structure in vibration-rotation bands. One expects that there should be no problem with photometric accuracy; yet, before embarking on a systematic program of study, we believe it important to establish that the method will work in practice. As a test case we have chosen the V2 fundamental of CO2 at 673 cm−1 since this is, in our experience, as difficult a band as any when it comes to measuring integrated intensities. We have, using a Digilab FTS-20 spectrometer, determined a value of the integrated intensity, Γ2 = 7901 ± 105 cm2/mol which should be compared with the value previously determined on a dispersive instrument, Γ2 = 7882 ± 110 cm2/mol. We have also determined a value of Γ3 = 25,300 ± 570 cm2/mol for the integrated intensity of the antisymmetric stretching fundamental.

Structural Effects on Nitrile Infrared Integrated Intensities of Alpha,Beta-Diaryl Cyanoethylenes: Hammett and Quantum Chemical Approaches

1978 ◽  
Vol 33 (5) ◽  
pp. 557-563 ◽  
Author(s):  
Ivan Juchnovski ◽  
Rositza Kuzmanova ◽  
Jordan Tsenov ◽  
José Kaneti ◽  
Ivan Binev
Keyword(s):  
Steric Hindrance ◽  
Quantum Chemical ◽  
Nitrile Group ◽  
Structural Effects ◽  
Mo Calculations ◽  
Infrared Intensities ◽  
Substituent Constants ◽  
Alpha Beta ◽  
Integrated Intensities ◽  
Derivatives Of

AbstractThe nitrile infrared intensities of a series of a,β-diaryl cyanoethylenes were juxtaposed to the associated substituent constants, HMO and SCF-MO indices and fair to excellent correlations were established. The competitive resonance of the nitrile group with alpha-and beta-aryl substituents is discussed. HMO calculations were used to estimate the steric hindrance to conjugation caused by polycyclic substituents and SCF-MO calculations were made to obtain uniform predictions of nitrile intensities and frequencies for hetero-cyclic derivatives of acrylonitrile.

Infrared Intensities of Liquids XII: Accurate Optical Constants and Molar Absorption Coefficients between 6225 and 500 cm−1 of Benzene at 25°C, from Spectra Recorded in Several Laboratories

1993 ◽  
Vol 47 (7) ◽  
pp. 891-911 ◽  
Author(s):  
John E. Bertie ◽  
R. Norman Jones ◽  
C. Dale Keefe
Keyword(s):  
Refractive Index ◽  
Absorption Coefficient ◽  
Primary Standard ◽  
Molar Absorptivity ◽  
Extensive Study ◽  
Molar Absorption Coefficient ◽  
The Real ◽  
Use Of Data ◽  
Liquid Benzene ◽  
Integrated Intensities

This paper presents the results of a study to obtain accurate infrared absorption intensities of liquid benzene at 25°C. To achieve this we have determined the agreement between the intensities measured by different spectroscopists using the same instrument in the same laboratory and also by different spectroscopists in different laboratories using instruments made by different manufacturers. The agreement between integrated intensities over specific wavenumber ranges has been found to average about 2%. The spectra from the different laboratories have been averaged, unweighted, to give intensity spectra of benzene that are presented as the best available. The use of data from different instruments in different laboratories has reduced the influence of systematic instrumental errors, so that the agreement presented should be a better approximation to the accuracy of the intensities than would be the case from an extensive study by one person on one instrument. The intensity data presented agree with the only measurements that have been made against a primary standard, the evaluated uncertainty of which is about 6%. The results are presented in both graphic and tabular forms as spectra of the molar absorption coefficient, Em(ν˜), (also called the molar absorptivity, ε, formerly the extinction coefficient) and the real and imaginary refractive indices, n(ν˜) and k(ν˜), between 6225 and 500 cm−1. The peak heights and the areas under the bands in the imaginary refractive index spectrum are reported, together with the peak heights and the areas under the bands in the molar absorption coefficient spectrum. Imaginary refractive index, k(ν˜), and molar absorption coefficient, Em(ν˜), values are believed accurate to an average ±2% at the peaks of stronger bands, ±3.5% at the peaks of the weaker bands below 4100 cm−1, and ±2.5% above 4100 cm−1. The baseline k(ν˜) values are accurate to ∼10% above 1200 cm−1 and 1% to 5% below 1200 cm−1. The areas under bands or band groups in k(ν˜) and Em(ν˜) spectra are accurate to 2% on average, or 1.5% when measured above a baseline for calibration purposes. The real refractive index, n(ν˜), values are believed accurate to 0.2%.

Electron thermalization distances and free-ion yields in dense gaseous and liquid benzene

1992 ◽  
Vol 70 (6) ◽  
pp. 1618-1622 ◽  
Author(s):  
Norman Gee ◽  
Gordon R. Freeman
Keyword(s):  
Three Dimensional ◽  
Dielectric Constants ◽  
Zero Field ◽  
Fluid Density ◽  
Model Assumption ◽  
Liquid Benzene ◽  
Free Ion ◽  
Ion Yields ◽  
Yield Formula ◽  
Reduced Density

Electron thermalization has been studied in gaseous and liquid benzene at 4.1 ≤ d/kg m−3 ≤ 878 (temperatures 295–560 K) using measurements of the free-ion yield [Formula: see text] as a function of electric field strength E and temperature T. The measured [Formula: see text] values at each T were compared to those calculated using an extended Onsager model. Assumption of a three-dimensional Gaussian distribution of secondary electron thermalization distances YG resulted in too large a field dependence. The Gaussian with the small added tail, YGP, gave the correct dependence. Values of the yield extrapolated to zero field, [Formula: see text] and of the most probable thermalization distance bGP were obtained. Variation of the density-normalized distance bGPd with reduced density d/dc (dc = critical fluid density) was expected to be similar to that in ethene, due to the π-electrons in the two compounds. Instead, it was similar to that in ethane. Throughout the liquid range, epithermal electrons were de-energized less efficiently than in the gas at d < 0.5 dc where the benzene molecules are further apart. As the density increases above 2 dc the values of bGPd decreased as in other hydrocarbons, rather than like those in hexafluorobenzene, which increased sharply. Dielectric constants were also measured up to 560 K.

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