Observed Interference Fringes Research Articles

The infrared spectrum of benzene in a solid HCl “matrix”

Studies are presented of the infrared absorption spectrum of benzene in an HCl “matrix” (HCl :benzene mole ratio of about 10:1). These results are compared in both frequency and intensity with the spectrum of crystalline benzene and of “glassy” benzene. The pathlengths needed to obtain the intensities of these thin solid films have been measured by observing interference fringes at a fixed wavelength as the film is deposited. In general, the spectra in all these phases (crystal benzene, “glassy” benzene, and complexed benzene) are similar. Splittings observed in the crystal disappear in the other two phases; otherwise frequencies are quite similar. A number of absorption bands, forbidden in the spectrum of the pure crystal, appear weakly in the “glass” and/or in the spectrum of benzene in the matrix. Also the intensity of the gas-phase allowed fundamentals ν 18 and ν 20, show a surprising decrease in the HCl matrix. The quantitative comparison of these relatively small changes observed in the spectrum of benzene in these different phases suggests benzene in the HCl matrix is in a site of approximately D 6 h symmetry, but is strongly perturbed.

Absolute Infrared Intensities of the Fundamental Absorption Bands in Solid Carbonyl Sulfide

Absolute infrared intensities for the fundamental absorption bands of COS have been measured in polycrystalline solid films. The path length has been measured by observing interference fringes. The results are in fair agreement with the intensities computed from the gas-phase values, corrected for the simple ``field effect,'' except for the very weak band, ν2. These results, together with those reported earlier for other linear triatomic molecules, are examined critically in a search for patterns of behavior. The ``intensity sum rule'' for crystals is restated. It is concluded that the spectra of these crystals are good examples of those to be expected for weak ``chemical'' interactions.

Absolute Infrared Intensities of the Fundamental Absorption Bands in Solid CO2 and N2O

Absolute infrared intensities of the fundamental vibrations of CO2 and N2O have been measured in polycrystalline solid films. The path length has been measured by observing interference fringes. In contrast with CS2, the results for the solid phase do not agree exactly with those predicted from the gas phase values, using only the simple ``field-effect'' correction. In particular the intensity in the solid is less than that in the gas phase for v1 and v3 of N2O and for v3 of CO2, whereas the ``field-effect'' predicts an increase in intensity. However, the observed changes in intensity are relatively small. The predicted frequency shifts also do not agree with the observed values, indicating that other effects are important. Bond moment parameters are presented. The bond moment μ is the same as in the gas phase, but the derivative, ∂μ/∂r, decreases by about 25%. Some incomplete studies of the intensities in mixed crystals of N2O and CO2 are presented.

Some galvanomagnetic and optical properties of Cu doped InSb films

InSb layers have been prepared by the “three temperature” evaporation technique, and their galvanomagnetic and optical properties were measured over a range of temperatures. The layers exhibited typical p-type characteristics with hole concentrations in the order of 10 17/cm 3 and electron/hole mobility ratios of approximately 32. Transmittance measurements were made for wavelengths between 2 and 40 microns for a range of sample temperatures. Changes in the refractive index may be determined from the behavior of the observed interference fringes. The lack of dispersion as well as the temperature dependence of the absorption is consistent with p-type behavior.