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The KnowledgeBank at OSU (76.105 recursos)

Knowledge Bank contains collections of presentations, publications and reports related to Ohio State University.

Abstracts of OSU International Symposium on Molecular Spectroscopy 1970-1979

Mostrando recursos 1 - 20 de 3.443

  1. VIBRATIONAL STUDIES OF RELATED MONOSUBSTITUTED PYRIDINES

    Kimmel, Howard S.; Abdel Shafy, Hussein I.
    The infrared and Raman spectra of pyridine, 2-, 3-and 4-chloro, bromo and methylpyridines, 2-fluoro, 2- and 4-iodo, 2-amino, 4-ethyl, and 4-vinylpyridines have been measured. Tentative assignments of the observed frequencies of 2-amino, 4-ethyl, 4-vinyl and the iodopyridines are reported for the first time. The infrared data for 2-fluoro-pyridine was combined with previously reported Raman data to allow complete vibrational assignments of this compound. Correlations between related series of pyridine derivatives are investigated. Further, possible correlations between the vibrations of monosubstituted pyridines and the corresponding vibrations of monosubstituted benzene compounds were studied.

  2. RAMAN DEPOLARIZATION RATIOS AND THE SYMMETRY OF Si (NCO)4 AND Ge $(NOC)_{4}$

    Snider, A. Monroe; Miller, Foil A.
    This study of silicon and germanium tetraisocyante was undertaken to determine whether the $M - N = C = O$ group is linear or bent (presumably at the nitrogen atom). The molecules would have tetrahedral symmetry if the ligand is linear, a configuration that presumably would occur if $p_\pi-d_\pi$ bonding exists between the nitrogen and the M atom. Tetrahedral symmetry requires the depolarization ratio, $\rho$, for totally symmetric fundamentals must be zero. An earlier study in 1961 (1) reported that ``the data for $Si(NCO)_{4}$ fit a tetrahedral model fairly well” and that ``$Ge(NOC)_{4}$ deviates in some unknown way from being...

  3. THE NORMAL MODES OF CYCLOPROPENONE

    Tuazon, E. C.; Miller, Foil A.
    The C = C stretching frequencies of cyclopropenone and cyclopropenone-$d_{2}$ present [FIGURE] a puzzling problem. They are presumably the very intense and strongly polarized Raman bands at 1480 and 1409 $cm^{-1}$, respectively. These unusually low values are in sharp contrast to those observed when the substituents are methyl, chloro, of phenyl, for then the C = C frequencies are in the ``normal” range of $1620 - 1680 cm^{-1}$. The low values for H and D raise a question about the proper description of the normal mode involved in these cases. A normal coordinate analysis of cyclopropenone-$d_{0}$ and $-d_{2}$ has been...

  4. VIBRATIONAL SPECTRA AND ASSIGNMENTS FOR TWO FLUOROCYCLOPOPENES

    Craig, Norman C.; Parkin, Kathleen M.; Spiegel, David A.
    A complete assignment of vibrational fundamentals has been obtained for 1 H-trifluorocyclopropene-$d_{0}$ and -$d_{1}$. Low symmetry of the molecule has been an asset in this case. Based on normal coordinate calculations as well as spectra provisional assignments are given for 3,3-difluorocyclopropene-$d_{0}$ nd -$d_{2}$. Some generalizations concerning group frequencies in cyclopropenes will be offered.

  5. INTERPRETATION OF THE VIBRATIONAL SPECTRA OF SMALL RING SYSTEMS: PERFLUOROCYCLOBUTANE

    Harris, W. C.; Yang, D. B.
    The vibrational spectra of gaseous and solid perfluorocyclobutane have been interpreted in terms of a planar molecule with $D_{4h}$ symmetry in view of the observed mutual exclusion between the infrared and Raman frequencies. A vibrational assignment for perfluorocyclobutane is presented and based upon the observed infrared and Raman band contours, depolarization ratios, relative and intensities and positions. A comparison of the ring-puckering potential functions and skeletal structures of cyclobutane, 1,1-difluorocyclobutane, trimethylene oxide and 3,3-difluoroexetane suggests the inversion barrier is reduced significantly upon introduction of a $CF_{2}$ group in the cyclic systems. The apparent trend toward planarity appears to continue in...

  6. LOW FREQUENCY VIBRATIONAL SPECTRA AND RING-PUCKERING OF CYCLOPENTENE-$d_{8}$

    Villarreal, J. R.; Laane, J.; Harris, W. C.
    The ring-puckering potential energy function for cyclopentene-$d_{8}$ has been determined from its vibrational spectra. The potential function and barrier are consistent with previous analysis of cyclopentene-$d_{0}$. In the Raman spectrum of the vapor, a dozen bands corresponding to $\Delta v = \pm\ 2$ puckering transitions were observed.

  7. LOW FREQUENCY VIBRATION SPECTRA AND RING-PUCKERING OF BICYCLOHEPTENES

    Villarreal, J. R.; Laane, J.
    The infrared and Raman spectra of bicyclo (3.2.0) hept-6-ene and bicyclo (3.2.0) hept-2-ene have been examined. The vapor phase Raman spectrum of the former compound shows several closely spaced bands near 240 $cm^{-1}$ corresponding to ring-puckering transitions. This is consistent with a boat structure which is considerably lower in energy than a chair conformation. Results for the latter compound will also be discussed.

  8. VIBRATIONAL SPECTRA AND RING-PUCKERING OF 1,3-DISILACYCLOBUTANE

    Irwin, R. M.; Laane, J.
    1,3-Disilacyclobutane has been prepared and preliminary vibrational spectra have been recorded. Sum and difference bands resulting from the ring-puckering mode have been observed in both infrared and Raman spectra in the $SiH_{2}$ stretching region. A preliminary potential energy function for the ring-puckering indicates a potential barrier of approximately 100 $cm^{-1}$.

  9. THE VIBRATIONAL SPECTRUM AND INTERNAL ROTATION OF DIMETHYLCYANAMIDE, DIMETHYLCYANAMIDE-$d_{3}$, AND DIMETHYLCYANAMIDE-$d_{6}$

    Blackwood, H. DeWitt; Brown, Farrell B.
    The vibrational spectrum of dimethylcyanamide has been reinvestigated. Two deuterium substituted isotopes, previously unreported, have also been investigated. The gaseous, liquid, and solid phase infrared spectra of all three compounds are reported for the region 4000 $cm^{-1}$ to 33 $cm^{-1}$. In addition, the Raman spectrum of each compound has been observed. Assignments of fundamental vibrational modes are proposed and torsional barriers calculated.

  10. THE VIBRATIONAL SPECTRA OF TRIMETHYL ORTHOTRIFLUOROACETATE

    Snyder, William H.; Kimmel, Howard S.; Mensah, P.
    The infrared and Raman spectra of trimethyl orthotrifluoroacetate have been determined in the gaseous, liquid and solution phases. Assignment of the fundamental vibrational frequencies will be discussed and compared with other similar molecules.

  11. THE INTERPRETATION OF INFRARED AND RAMAN SPECTRA USING A BINARY CLASSIFIER

    Comerford, John M.; Snyder, William H.; Kimmel, Howard S.
    Using data from the recently published Sadtler Standard Raman Spectra, pattern recognition techniques were used to investigate digitized infrared and Raman spectra. Binary pattern classifiers were developed for several chemical classes, using both the infrared and the Raman spectra. High predictive abilities have been obtained in classifying unknown spectra. The vectors calculated for a particular class of compounds using several types of vibrational spectra have been compared in order to develop an aid in assigning vibrational frequencies. In addition, data developed by combining infrared and the several types of Raman spectra have been examined with this technique.

  12. VAPOR-PHASE RAMAN SPECTRA AND RING-PUCKERING OF BICYCLO (3.1.0) HEXANE AND RELATED COMPOUNDS

    Lewis, J. D.; Laane, J.; Malloy, Thomas B., Jr.
    Low-frequency gas phase Raman spectra have been recorded for bicycle (3.1.0) hexane, 3-oxabicyclo (3.1.0) hexane, 6-oxabicyclo (3.1.0) hexane, and 3, 6-dioxabicyclo (3.1.0) hexane. Raman transitions resulting from the out-of-plane ring modes have been assigned for each molecule. Ring-puckering transitions were observed for each molecule except 3,6-oxabicyclo (3.1.0) hexane. Six puckering transitions were observed for bicyclo (3.1.0) hexane, from which was derived an asymmetric single-minimum potential energy function of the form V = 24.70 ($Z^{4} + 25.72 Z^{2} + 9.28 Z^{3})$ $cm^{-1}$, where Z is the reduced puckering coordinate. The Raman results strongly indicate that bicyclo (3.1.0) hexane has a single...

  13. DIPOLAR BROADENING OF MAGNETIC RESONANCE LINES: A TOOL FOR STUDY OF DIMERIZATION AND CLUSTER FORMATION

    Menzel, E. R.; Wasson, John R.
    The ESR spectra of several copper (II) dithiocarbamates in a variety of solvents were investigated at room temperature in the concentration range of $10^{-3}$ to $10^{-1}$M. A very pronounced broadening of the magnetic resonance lines is observed at the higher concentrations. This broadening could not be interpreted by the Brownian motional model of Bloembergen, Purcell, and Pound, or similar theoretical formulations. The method of moments developed by Van Vleck for crystalline magnetic systems and extended to magnetically dilute crystalline cases by Kittel and Abrahams is adapted to solution cases involving molecules of size such that the motional correlation times become...

  14. MEASUREMENTS OF LINE WIDTH AND SHIFT PARAMETERS FOR MICROWAVE ABSORPTION LINES

    Kakar, Ramesh K.; Poynter, R. L.
    The line width and shift parameters have been measured in the same experiment, with the aid of a computer controlled microwave spectrometer. The technique can be employed to rapidly and reproducibly measure these parameters for any microwave spectral line. As a test of this experimental method, the width and shift parameters were measured for the K = J self-broadened ammonia inversion lines. With a few exceptions, the width measurements are in general agreement with the work of Legan, et $al.^{1}$ However, the line shift parameters generally disagree with the values obtained by previous workers. The ammonia results and some preliminary...

  15. ON THE DETERMINATION OF THE QUADRUPOLE MOMENT OF OXYGEN FROM SELF-BROADENED LINE WIDTHS IN THE MICROWAVE SPECTRUM

    Sarangi, Sunil; Varanasi, P.
    The large discrepancy between the value 0.4D {\AA} measured by Buckingham for the quadrupole moment of oxygen and the recent value 1.21D {\AA} used by Yamamoto and Cattani, and by Bouanich, in line broadening calculations is examined. When hexadecapolar and repulsive interactions are included, the discrepancy in the values of the quadrupole moment obtained by the bi-refringence method and line width calculations is at once resolved provided a value of $\Phi \sim$ 6D {\AA}$^{3}$ is used for the hexadecapole moment of oxygen.

  16. ROTATIONAL RELAXATION IN OCS

    Brown, Steven R.; Creswell, R. A.; Schwendeman, R. H.
    The pressure dependence of the polarization relaxation time, $T_{2}$, has been determined for the J = 1 $\rightarrow$ 2 rotational transition in OCS by measuring the linewidth of the transition, the exponential rise time of on-resonant transient absorption, and the exponential decay time of off-resonant transient absorption-emission. The values of the numbers obtained are nearly equal for all three experiments. However, the linewidth parameter is 2--5\% smaller than previously reported values. Also, the results for the transient experiments, expressed as a linewidth parameter, are slightly larger than the steady-state linewidth measurements. The possible reasons for these discrepancies will be discussed.

  17. MICROWAVE SPECTRUM OF METHYLDIFLUOROPHOSPHINE BORANE

    Creswell, R. A.; Elzaro, R. A.; Schwendeman, R. H.
    The microwave spectrum of methyldifluorophosphine borane $(CH_{3}PF_{2}BH_{3})$ has been observed in the region 18.0 to 40.0 GHz. Transitions with a and b-type selection rules have been assigned for both boron isotopes in the normal and $BD_{3}$ compounds. A barrier to internal rotation for the $CH_{3}$ group has been determined from ground state splittings in the parent species. The dipole moment and its components have been determined from an analysis of the Stark effect. Structural information has been derived from the observed rotational constants.

  18. USE OF FORBIDDEN TRANSITION FOR A BETTER DETERMINATION OF MOLECULAR PARAMETERS IN THIONYL FLUORIDE MOLECULE

    Dubrulle, A.; Boucher, D.; Burie, J.
    The thionyl fluoride molecule belongs to the point group $C_{s}$, and the electric dipole moment components on the principal axes are $\mu_{a}$ and $\mu_{c}$. The determination of molecular parameters has been obtained from a and c type $transitions.^{1,2}$ By the application of an electric field, forbidden b type transitions may be observed. A better definition of molecular parameters has been obtained by use of these results.

  19. MICROWAVE SPECTRA AND STRUCTURE OF DIMETHYLPHOSPHINEBORANE

    Hudgens, B. A.; Durig, J. R.
    The microwave spectra of six isotopic species of dimethyl-phosphineborane, $(CH_{3})_{2}HP^{11}BH_{3}$, $(CH_{3})_{2}H^{10}BH_{3}$, $(CH_{3})_{2}DP^{11}BH_{3}$, $(CH_{3})_{2}DP^{10}BH_{3}$, $(CH_{3})_{2}HP^{11}BD_{2}H$ and $(CH_{3})_{2}HP^{11}BD_{3}$ have been recorded and an $r_{o}$ structure obtained.

  20. MICROWAVE SPECTRUM OF SULFUR OXIDE TETRAFLUORIDE

    Shoemaker, Charles F.; Gum, Mary L.; Graybeal, Jack D.
    The electron diffraction studies of $SOF_{4}$ were initially interpreted to show that the molecule was in a trigonal bipyramid structure with a near trigonal structure in the equatorial plane and the axial F-S-F configuration bent slightly toward the equatorial $oxygen.^{1}$ Following the publication of Gillespie’s bonding concepts and the effect of electron pair repulsion, the authors revised their interpretation to show that the equatorial FSF angle was decreased and the axial F-S-F configuration was bent away from the equatorial $oxygen.^{2}$ The microwave spectrum of $SOF_{4}$ has been investigated in the 12.5 to 18 GHz region and 79 lines belonging to...

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