151 research outputs found

    A new sputtering apparatus

    Get PDF
    The writer, in sputtering a large number of mirrors, has found that the apparatus and methods to be described have several advantages, particularly where very large and perfect mirrors are desired. The accompanying diagram will be self explanatory, and the dimensions given have been found convenient for mirrors up to 10 cm diameter

    Note on the Spectra of the Disubstituted Acetylenes and of the Mustard Oils

    Get PDF
    It has been observed that in the Raman spectra of many disubstituted acetylenes the line corresponding to the so-called C≡C frequency is split into two components of not greatly different intensity (1), though this is not the case in the monosubstituted compounds. In the mustard oils the C≡N Raman line is double (2), and in allyl mustard oil (3), the one substance which appears to have been studied with sufficient dispersion, the corresponding infrared band shows definite indications of splitting into two components. This doubling is not observed in the organic thiocyanates. These facts have caused some speculation so far appear never to have received a satisfactory explanation. The presence of two fundamentals in the 2200 cm^-1 region appears quite impossible for most of the molecules showing the doubling, and on the other hand the coexistence of two forms of molecule with slightly different frequencies appears unlikely, especially in the case of the acetylenes. Consequently the author proposes an explanation involving a Fermi resonance interaction between the C≡C or C≡N fundamental, as the case may be, and the overtone of a certain other vibration of approximately one-half or one-third the frequency

    The Relation Between the Energy of a Hydrogen Bond and the Frequencies of the O[Single Bond]H Bands

    Get PDF
    It has previously been pointed out (1) that there appears to be a relation between the energy of a hydrogen bond and the shift of the frequency of the O-H bands which accompanies the formation of the bond. Recently additional data have been obtained in this laboratory (2,3) which confirm the existence of this useful relation and it seems worth while to discuss them in this connection. The data here presented all relate to linkages in which a hydroxyl hydrogen is concerned, though the atom to which it is weakly bound may be oxygen, chlorine, or carbon in an aromatic ring. It is surprising that the same connection between energy and frequency shift should be found in these various cases but such appears to be the fact. For other types of bond, for example those involving the hydrogen of an amino group, a slightly different relation may well be expected

    Two devices facilitating spectrometry in the far infrared

    Get PDF
    In spectrometric investigations in the infrared two principal difficulties are the extremely small energy available in the long waves, and the relatively great intensity of the near infrared. This latter is of particular importance in using an echlette grating which reflects the short waves with great intensity in high orders. The arrangement here described was devised to overcome both of these inconveniences

    A Microilluminator for the Study of the Infrared Spectra of Small Samples at Low Temperatures

    Get PDF
    An instrument is described which combines the functions of a reflecting microscope and a low temperature cell. It permits infrared absorption spectra to be obtained on single microcrystals at low temperatures, using polarized radiation

    The infrared spectra of HOCl and DOCl

    Get PDF
    We have recently observed the spectra of hydrogen hypochlorite and deuterium hypochlorite in the region 1-15μ as part of a general program of study of simple molecules. Since, so far as we are aware, no spectroscopic data has heretofore been reported on these substances, the preliminary results are of sufficient interest to be presented at this time

    The infra-red spectrum and molecular structure of HNCS

    Get PDF
    From an examination of the microwave spectra of four isotopic species of isothiocyanic acid, Beard and Dailey (1) recently obtained the following values for the molecular parameters in the ground vibrational state

    On the Pressure Broadening in the Gamma Bands of Nitric Oxide

    Get PDF
    A quantitative investigation of the pressure broadening in the γ(0,0) and γ(1,0) bands of nitric acid established that the pressure effect is not abnormal as has sometimes been supposed and that the collision diameter of the excited NO molecule is approximately 3.8 Å

    Spectra of Urea and Thiourea in the 3µ Region

    Get PDF
    Observations are reported on the polarized infrared spectra of single crystals of urea and thiourea in the 3µ region. Complex structures accompanying the N [Single Bond] H fundamentals appear, at least in considerable part, to be attributable to combinations and overtones of fundamentals in the neighborhood of 1650 cm^—1
    • …
    corecore