Showing papers on "Resonance published in 1970"
TL;DR: The radio frequency spectrum of HF and DF was measured by the molecular-beam electric resonance method as mentioned in this paper, and the measurements were in the lowest vibrational state (υ) = 0 and first rotational state(J) = 1.
Abstract: The radio frequency spectrum of HF and DF is measured by the molecular‐beam electric resonance method. The measurements are in the lowest vibrational state (υ = 0) and first rotational state (J = 1). The constants obtained are: HFDFμ (D)1.826526 (7)1.818805 (5)CF (kHz)307.637 (20)158.356 (45)CH (kHz)− 71.128 (24)− 5.755 (19)SHF (kHz)28.675 (5)4.434 (9)JHF (kHz)0.529 (23)(eqQ) D354.238 (78) The electron coupled spin–spin interaction, JHF = + 530 Hz.
300 citations
TL;DR: In this article, the effect of proton decoupling on carbon-13 magnetic resonance spectra is treated in detail with the Solomon formulation for multiply irradiated spin systems, and the factors affecting the nuclear overhauser enhancement are discussed in terms of competition between the dipole-dipole relaxation mechanism essential to the Overhauser effect and other relaxation processes.
Abstract: The effect of proton decoupling upon carbon‐13 magnetic resonance spectra is treated in detail with the Solomon formulation for multiply irradiated spin systems. The factors affecting the nuclear Overhauser enhancement are discussed in terms of competition between the dipole–dipole relaxation mechanism essential to the Overhauser effect and other relaxation processes. Using a density matrix formulation, it is exhibited that the maximum Overhauser effect (achieved when the dipolar mechanism dominates) is independent of the number of hydrogen atoms interacting with a relaxing carbon‐13 nucleus. On the other hand, if the molecular tumbling motion is isotropic and the dipole–dipole mechanism dominates the relaxation process, then to a first approximation T1 can be shown to depend inversely upon the number of directly bonded hydrogen atoms. Expressions for treating an AMX three‐spin system are given also, and the effect of the third spin is discussed. The highly symmetric adamantane molecule provides an excell...
252 citations
TL;DR: In this article, the effects of l-type resonance on rovibrational bands in infrared spectra are reviewed and compared with computer-simulated spectra obtained by solving the Hamiltonian matrix numerically and calculating the true (perturbed) wavenumber and intensity of each line in the band.
235 citations
TL;DR: In this article, the difference between the two types of spectra are discussed in some detail, and the relative scattering cross sections are given for the fundamentals and overtones of Cl2, Br2, I2, ICI, and IBr at 4880 A excitation.
Abstract: The various output frequencies of the argon ion laser at 5145, 5017, 4965, 4880, and 4765 A lie in the absorption bands of the heavier halogen gases. With the appropriate choice of exciting line, either resonance Raman effect or resonance fluorescence can be observed. The difference between the two types of spectra are discussed in some detail. In the case of a strong resonance Raman effect, overtone sequences up to the 14th harmonic could be observed. Raman frequencies, depolarization ratios, and relative scattering cross sections are given for the fundamentals and overtones of Cl2, Br2, I2, BrCl, ICI, and IBr at 4880 A excitation.
224 citations
TL;DR: Ion cyclotron resonance spectroscopy has been adopted for the detection of gaseous ions formed within an analyzer cell of new design as discussed by the authors, which has been trapped by electron impact for as long as 0.10 sec and detected with a half-height mass resolution of 5000.
Abstract: Ion cyclotron resonance spectroscopy has been adopted for the detection of gaseous ions formed within an analyzer cell of new design. Ions formed by electron impact have been trapped within the analyzer cell for as long as 0.10 sec and detected with a half‐height mass resolution of 5000. Even at pressures of 10−5 Torr ion‐molecule reactions of high kinetic order may be observed. An important feature of the trapped ion analyzer cell is that it retains the capability of the ICR double resonance experiment for elucidating the reaction sequence occurring in a complex mixture of primary ions and high order product ions. A pulsed magnetic field detection scheme accurately limits the residence time of the ions within the trapped ion analyzer cell.
171 citations
TL;DR: In this paper, it was shown that the broadening of wave-particle resonances by the random motion of particles in a turbulent electric field may determine the saturation level of a variety of high-frequency instabilities.
Abstract: It is shown that the broadening of wave‐particle resonances by the random motion of particles in a turbulent electric field may determine the saturation level of a variety of high‐frequency instabilities. Secular changes of the guiding center positions, cyclotron radii, and phase angles give rise to resonance broadening and diffusion, similar to that produced by collisional scattering. The field dependent broadening is expressed in terms of resonance functions which replace the familiar resonant denominators of the linear theory. Resonance functions are derived in a simple manner from the solution of a Brownian motion problem, leading to an expression in terms of diffusion coefficients. The close resemblance of the theory to quasilinear theory and the linear theory including collisions allows one to start from a linear stability analysis and then assess the importance of nonlinear effects. This method is illustrated by the determination of the saturation level of cyclotron instabilities from the condition of vanishing nonlinear growth rate.
146 citations
TL;DR: The detection of resonance Raman (RR) scattering of laser radiation from vibrational modes in the molecules of the carotenoid pigments12–14 lycopene and β-carotene in intact plant samples is reported.
Abstract: WE report here the detection of resonance Raman (RR)1–11 scattering of laser radiation from vibrational modes in the molecules of the carotenoid pigments12–14 lycopene and β-carotene in intact plant samples (Figs. 1a and b). Resonance enhancement is obtained in the Raman spectra of pigments excited at wavelengths in the region of electronic absorption. The effect is manifest in a conspicuous gain in the scattering efficiency from some of the vibrational modes of the pigment. The scattered light becomes sufficiently intense to overcome the increased absorption losses of both the exciting and the scattered radiation. In this study we have demonstrated this effect in heterogeneous (tissue) samples, in which the pigment is just one constituent.
125 citations
117 citations
TL;DR: In this paper, the anharmonic phonon-phonon interactions were studied by Green's function methods, and the twophon spectrum exhibits an asymmetric peak near the top of the two-phonic continuum.
Abstract: Considering the anharmonic phonon-phonon interactions, two-phonon resonances are studied by Green's-function methods. The two-phonon spectrum exhibits an asymmetric peak near the top of the two-phonon continuum. In the special case of a resonance consisting of two acoustic phonons, the hybridization of the resonance with a single optical phonon is possible, in agreement with experiment.
112 citations
TL;DR: In this article, the damping constants of resonant bubbles are extended to the off-resonance case and it is shown that thermal damping is important for bubbles driven below resonance, and radiation damping for those above resonance.
Abstract: Results obtained by Devin [J. Acoust. Soc. Amer. 31, 1654–1667 (1959)] for the damping constants of resonant bubbles are extended to the off‐resonance case. Calculated results show for the range of conditions considered that thermal damping is important for bubbles driven below resonance, and radiation damping is important for those above resonance.
103 citations
TL;DR: High resolution nuclear magnetic resonance spectroscopy is used to study conformational changes in histone fractions F2a1 and F1 when the ionic strength of aqueous solutions is raised and the proportion of amino acid residues incorporated into secondary structure is less than that involved in the conformationalChanges indicated by thenuclear magnetic resonance results.
Abstract: High resolution nuclear magnetic resonance spectroscopy is used to study conformational changes in histone fractions F2a1 and F1 when the ionic strength of aqueous solutions is raised. Increasing line widths of certain resonance peaks, in particular those of apolar and aromatic amino acids, together with sequence data lead to the conclusion that the C-terminal half of F2a1 and a central portion of F1 are involved in the conformational changes. The proportion of amino acid residues incorporated into secondary structure (as indicated by optical rotatory dispersion) is less than that involved in the conformational changes indicated by the nuclear magnetic resonance results. Intermolecular interactions are therefore postulated to explain this difference and these are specific in as much as they involve only a part of the histone molecule and include the regions of the chain having high potential for secondary structure formation.
TL;DR: Differences in the ring-current-shifted resonances amongst various ligated forms including cyanoferrimyoglobin, indicate the existence of structural differences in the protein when the ligand is changed.
TL;DR: Analysis of the shifts suggests that an aromatic side chain ring lies near the edge of the heme ring in theyanide-inhibited electron exchange between ferri- and ferrocytochrome c molecules observed by nuclear magnetic resonance.
Abstract: Cyanide-inhibited electron exchange between ferri- and ferrocytochrome c molecules has been observed by nuclear magnetic resonance. Irradiation of a partially reduced protein solution at resonance frequencies arising from protons of the oxidized state results in a decrease in the absorption due to the corresponding protons of the reduced state. The experiment quantitates the hyperfine shifts observed in this system and can be used to identify hitherto unassignable resonances. Analysis of the shifts suggests that an aromatic side chain ring lies near the edge of the heme ring.
TL;DR: In this paper, the first Raman study employing a UV laser was performed and multiphonon zone center scattering processes were observed, as well as resonance with the scattered photon.
TL;DR: In this article, the Hanle effect and recrossing effect were used to estimate the dipole moment of carbon monosulfide in the R(7) transition of the 0-0 band.
Abstract: Using the coincident atomic spectral line MnII 2576.1 to pump the R(7) transition of the 0–0 band, level crossing and double resonance are observed in the 1Π state of carbon monosulfide. From the Hanle effect a lifetime value of 2.0 ± 0.4 × 10−7 sec is obtained. The analogous Stark level crossing effect and the Stark–Zeeman recrossing effect give estimates of the dipole moment μ and lambda doubling δ. With an rf search aided by these estimates, optical‐rf double resonance provides more accurate values: μ8 = 0.68 ± 0.01 D; δ8 = 1099.4 ± 0.3 MHz for the J = 8 level. Considering the effect of nearby perturbing states, it is estimated that μΠ = μ8 ± 0.08 D. A derivation of signal intensity for the double resonance experiment is used to obtain the rf power requirements and criteria for selecting the optimum polarization.
TL;DR: In this article, it was shown that the unconstrained layer technique can be equal in damping effectiveness to the four-layer beam construction with the same total thickness of damping layers only when the modulus of elasticity of the non-constraint layer is of the same order of magnitude as for metals.
TL;DR: In this paper, the relation between an anomalous intensity effect in patterns from high energy electron diffraction by crystals, and the so-called resonance effect in LEED, is discussed mainly on the basis of experimental observations with electrons in both energy ranges, using crystals of zincblende, magnesium oxide and gallium arsenide.
Abstract: The relation between an anomalous intensity effect in patterns from high energy electron diffraction by crystals, and the so-called resonance effect in LEED, is discussed mainly on the basis of experimental observations with electrons in both energy ranges, using crystals of zincblende, magnesium oxide and gallium arsenide. It is concluded that these two effects are essentially of the same nature. It is pointed out, that the intensity enhancement of the specular spot and other Laue-zone spots, which occurs under conditions of resonance, is particularly conspicuous when the specular spot is also a Bragg reflection spot. The nature of the wavefield generated in the crystal at resonance is discussed in connexion with other phenomena which appear under the resonance condition, such as the overall intensity enhancement of electron scattering, the increase of secondary electron emission and the variation of X-ray emission yield.
TL;DR: In this paper, a newly designed ion-cyclotron resonance (ICR) cell is used to investigate kinetic energy dependence in ion-molecule reactions in methane, hydrogen, and rare gas-hydrogen systems.
TL;DR: An NMR double resonance study of a mixture of ferricy tochrome c and azidoferricytochrome c reveals the presence of an exchange of azide ions between the protein molecules.
TL;DR: In this paper, an optically detected electron-electron double resonance (EEDOR) experiment is demonstrated on the triplet state of pyrimidine by using two concentric microwave helices.
TL;DR: In this article, the authors measured the multiplet oscillator strength for the resonance triplets of N and O using the line absorption method and measuring atom concentrations by chemical titration.
Abstract: Multiplet oscillator strengths, ΣgLfLU, for the resonance triplets of N and O were determined using the line absorption method and measuring atom concentrations by chemical “titration.” For the NI triplet at 1200 A, ΣgLfLU = 0.87 ± 0.20, and excellent internal agreement was obtained among the separately measured fLU of the three lines. A value of (3 ± 1) × 10−11 cm3 sec−1 is required for the rate constant of the N+NO→N2+O reaction in the analysis of the data. For the OI triplet near 1300 A, the apparent ΣgLfLU increased sharply and reproducibly from 0.19 to 0.42 when the diluent gas in the discharge light source was changed from Ar to He, which indicates that excitation transfer is a major source of excitation in such Ar–O2 resonance lamps. The larger oscillator strength obtained with He–O2 light sources is in excellent agreement with results of lifetime measurements by other workers.
TL;DR: Advanced methods of phosphorus-31 nuclear magnetic resonance spectroscopy provided a method whereby biological phosphonates and phosphates can be determined on simple lipid fractions of biological origin.
Abstract: Advanced methods of phosphorus-31 nuclear magnetic resonance spectroscopy provided a method whereby biological phosphonates and phosphates can be determined on simple lipid fractions of biological origin. The spectra consist of two easily distinguished resonance bands; one corresponds to families of phosphonates, and the other corresponds to families of orthophosphates.
TL;DR: In this paper, the authors measured the thickness of thin, discontinuous silver sulfide tarnish films on a rough metal surface and found that the effect of the thin film should be the same as that of a continuous film whose thickness is the average thickness of the discontinuous film.
Abstract: The strong coupling between photons and surface plasmons that occur on rough metal surfaces permits optical measurements of the shift of the surface plasma resonance frequency when the metal surface is covered with a thin film Thin, discontinuous silver sulfide tarnish films on silver shift the resonance to lower frequencies and also damp the resonance, in agreement with surface plasmon dispersion theory The wavelength of the dominant surface plasma wave is large compared to the size of the discontinuities, so the effect of the thin film should be the same as that of a continuous film whose thickness is the average thickness of the discontinuous film On this basis, the thicknesses of several silver sulfide films are calculated from the measured frequency shift of the resonance peak and are found to be in excellent agreement with values determined from independent ellipsometric measurements