The infrared spectra of the formate, acetate, and oxalate ions have been obtained for both the solid and aqueous solution. The Raman spectra of these ions with depolarization ratios have been obtai...

The vibrational spectra of the formate, acetate, and oxalate ions

(1987). Applications of the interaction of microwaves with the natural snow cover. Remote Sensing Reviews: Vol. 2, No. 2, pp. 259-387.

Applications of the interaction of microwaves with the natural snow cover

Two rules are presented which relate the intensities of vibrational fundamentals of different isotopic species. They are thus analogous to the Teller‐Redlich product rule which relates frequencies. They apply to either infrared or Raman intensities. One rule permits the calculation of dipole‐moment derivatives without the determination of normal coordinates. The application of the rules is illustrated.

Vibrational Intensities. II. The Use of Isotopes

The transition behavior and dielectric properties of trifluoroethylene (TrFE)–vinylidene fluoride (VDF) copolymers were studied. The DSC and X-ray diffraction measurements indicated that the conformation of the polymers was in a crystalline state throughout the entire polymer composition, and crystallized isomorphically. In the thermal expansion measurement of the 56:44 TrFE–VDF copolymer, two breaks were observed, indicating two glass-to-rubber transitions. These two transitions were also observed in a mechanical relaxation study with peaks at 40°C (designated as β1) and −20°C (designated as β2), measured at 35 Hz. The β1-transition was tentatively assigned to the micro-Brownian motion of the main chain in the amorphous phase rich in TrFE-units; the β2-transition was assigned to the micro-Brownian motion of the main chain in the amorphous phase, rich in VDF-units. It was also found that the dielectric constant e′ of TrFE–VDF copolymer took on a maximum at 55 mol% VDF content. The numerical value of e′ was 15 (at 1 kHz and at 22°C) and about 1.7 times larger than those of poly(trifluoroethylene) and poly(vinylidene fluoride) homopolymers.

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Transition Behavior and Dielectric Properties in Trifluoroethylene and Vinylidene Fluoride Copolymers

The shapes and intensities of infrared absorption bands—A review

With spectrographs of available resolving power, the apparent integrated absorption coefficients of infra‐red bands usually differ greatly from the true coefficients because the spectrograph yields at each setting a weighted average of the fractional light transmitted in a band of frequencies, whereas what is desired is the unweighted average of the logarithm of the fractional light transmitted. It is shown that true absorption coefficients can be obtained by (a) eliminating the violent fluctuations in intensity with frequency by broadening the rotational lines with a non‐absorbing foreign gas and (b) eliminating the error due to the intensity variation of the envelope by extrapolating the apparent integrated absorption coefficient divided by the partial pressure to zero partial pressure of the absorbing gas. These two steps permit vibrational intensities to be measured to a reasonable accuracy even with a spectrograph of low resolving power.

The Experimental Determination of the Intensities of Infra‐Red Absorption Bands I. Theory of the Method

The infra‐red spectrum of gaseous nitromethane has been studied over the wave‐length range from 3 to 25 μ. The Raman work of Pendl, Reitz and Sabathy has been checked. These data together with a partial normal coordinate treatment enable us to make an assignment of the observed lines and bands which accounts for all the fundamental frequencies except the torsion around the C–N bond. The fundamental frequencies for the gas are 476, 599, 647, 921, 1097, 1153, 1384, 1413, 1449, 1488, 1582, 2965, 3048 (2). No decision regarding the potential barrier restricting the internal rotation of the methyl group can be made until at least one thermo dynamic quantity has been measured. The present results are compatible with the usual structure CH3NO2.

Infra‐Red and Raman Spectra of Polyatomic Molecules XIII. Nitromethane

The absolute intensities of the chief infra‐red absorption bands of ethylene and nitrous oxide have been determined experimentally to be (in cycles per centimeter at N.T.P.): Ethylene            Nitrous oxide          950 cm−1 band: 1540×1010590 cm−1 band: 120×10101444 cm−1 band:  210×10101285 cm−1 band:1150×10103050 cm−1 band:  840×10102224 cm−1 band:5600×1010 From these intensities it is possible to calculate the dipole moments, μ, of bonds between vibrating atoms and also the rates of change of dipole moment with inter‐nuclear distances, ∂μ/∂r. The values of μ obtained are all of the order of magnitude of 0.5×10−18 c.g.s. unit, while values of ∂μ/∂r are of the order of 1×10−10 c.g.s. unit. The results are in agreement with available data on infra‐red dispersion and on atomic polarization within the limits of experimental error, which are estimated to be approximately ±10 percent.

The Experimental Determination of the Intensities of Infra‐Red Absorption Bands II. Measurements on Ethylene and Nitrous Oxide

The infra‐red spectrum of gaseous propylene has been studied from 3 to 25μ with a spectrometer using fluorite, rocksalt and KBr prisms. A normal coordinate calculation of the fundamental frequencies has been made, using force constants obtained principally from ethylene and ethane. This information, when combined with the known Raman spectrum, permits an assignment of fifteen of the twenty fundamental frequencies and puts limits on four of the remaining frequencies.

A. J. Wells

Papers

The Experimental Determination of the Intensities of Infra‐Red Absorption Bands I. Theory of the Method

Infra‐Red and Raman Spectra of Polyatomic Molecules XIII. Nitromethane

The Experimental Determination of the Intensities of Infra‐Red Absorption Bands II. Measurements on Ethylene and Nitrous Oxide

Infra‐Red and Raman Spectra of Polyatomic Molecules XIV. Propylene

The Experimental Determination of the Intensities of Infra-Red Vibration-Rotation Absorption Bands of Gases