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  • 1
    Electronic Resource
    Electronic Resource
    Dependence of coercivity on the anisotropy field in the Nd2Fe14B-type sintered magnets (1987)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 3559-3561 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The temperature dependence of the coercivity (HcI)of Nd15(Fe1−xCox)77B8 and (Nd1−xDyx)15Fe77B8 sintered magnets and that of the saturation magnetization (Ms) and the anisotropy field (HA) of Nd2(Fe1−xCox)14B and (Nd1−xDyx)2Fe14B single crystals have been observed in the temperature range between 295 and 800 K. The dependence of the coercivity on the major magnetic properties of the matrix phase in the Nd-Fe-B based magnets are investigated using the μ0HA vs μ0HcI+Ms plot. It is demonstrated that this method of analysis is useful in studying the coercivity mechanism of the Nd-Fe-B based sintered magnets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.338725
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  • 2
    Electronic Resource
    Electronic Resource
    Magnetization and magnetic anisotropy of R2Fe14B measured on single crystals (1986)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 59 (1986), S. 873-879 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The temperature dependence of the saturation magnetization and the magnetocrystalline anisotropy field have been measured on single-crystal samples of the R2Fe14B compounds for R=Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Tm from 4.2 K to the magnetic ordering temperatures. A spin reorientation transition of the Nd2Fe14B type has been found in Ho2Fe14B at 57.6 K in zero field. Another type of spin reorientation caused by anisotropy compensation between the Fe and the R sublattices exists in Er2Fe14B and Tm2Fe14B. The temperature dependence of the angle of the easy direction of magnetization from the c axis has been measured for R=Nd, Ho, Er, and Tm. The relation between the magnetocrystalline anisotropy and the sublattice magnetization is investigated by employing a simplified two-sublattice molecular field model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.336611
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  • 3
    Electronic Resource
    Electronic Resource
    Investigation of trapping states in a Nb-doped rutile by admittance spectroscopy (1986)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 60 (1986), S. 4191-4196 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In order to obtain semiconductivity, rutile crystals have been doped with Nb by means of diffusion. The resulting Nb-doped rutile crystals have an electrical resistivity (approximately-equal-to)80 Ω cm at room temperature. Impedance analysis of a Nb-doped TiO2-Au diode suggests that the measurement frequency must be lower than 10 kHz to detect the capacitance and conductance of the depletion layer. Thus, an admittance spectroscopic method is used to study traps in the diode of the Nb-doped TiO2-Au. Two trap levels, located at 0.24 and 0.37 eV below the bottom of the conduction band, have been detected by this method. The state densities and capture cross sections of these trap levels are also determined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.337505
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  • 4
    Electronic Resource
    Electronic Resource
    Magnetization and magnetic anisotropy of R2Co14B and Nd2(Fe1−x Cox)14B measured on single crystals (1987)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 3571-3573 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Magnetization and anisotropy field of R2Co14B with R being La, Nd, and Gd and of Nd2(Fe1−xCox)14B have been measured on single-crystal specimens. The cobalt sublattice has a planar anisotropy: K1=−1.30 MJ/m3 at 4.2 K for La2Co14B with the [110] direction being the room-temperature easy direction of magnetization. The rare-earth ions in R2Co14B experience a smaller exchange field than in R2Fe14B, which results in a rapid reduction of the rare-earth sublattice magnetization and anisotropy with increasing temperature. Because of the planar anisotropy of cobalt and the weaker R-Co interactions than R-Fe, the anisotropy field of Nd2(Fe1−xCox)14B turns out to be almost independent of the cobalt concentration in a temperature range between 300 and 500 K.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.338729
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  • 5
    Electronic Resource
    Electronic Resource
    Reversed-phase retention behavior of aromatic compounds involving .beta.-cyclodextrin inclusion complex formation in the mobile phase (1986)
    s.l. : American Chemical Society
    Analytical chemistry 58 (1986), S. 2668-2674 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac00126a020
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  • 6
    Electronic Resource
    Electronic Resource
    Electron transfer in reactions of ketones with organolithium reagents. A carbon-14 kinetic isotope effect probe (1987)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 109 (1987), S. 4305-4308 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00248a027
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  • 7
    Electronic Resource
    Electronic Resource
    Application of the indirect dephasing model to resonance and dispersed fluorescence in the isolated molecular complex (1987)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 86 (1987), S. 2510-2517 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The theory of indirect dephasing proposed by Hiroike is applied to studying the mechanism of line broadening in resonance and dispersed fluorescence spectra of molecular complexes in supersonic free jet. In the indirect dephasing model, the width of the luorescence spectra which is characterized by the homogeneous linewidth can be expressed in terms of two parameters, the rate of intramolecular vibrational redistribution (IVR), γ and frequency change induced by the IVR, δω. It is shown that the non-Markovian character introduced into the interaction between the intra- and intermolecular modes reduces the indirect dephasing rate. The theory is applied to calculation of the linewidth of the resonance fluorescence of the tetrazine–Ar molecular complex excited in 6a1 vibronic level. The introduction of the non-Markovian character is necessary to calculate the linewidth of the fluorescence in a molecular complex with a few intermolecular modes such as tetrazine–Ar.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.452103
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  • 8
    Electronic Resource
    Electronic Resource
    Theory of coherent polarization anisotropy in time-resolved two-photon ionization of isolated molecules. Effects of Coriolis couplings (1987)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 87 (1987), S. 3418-3428 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Effects of vibration–rotation (Coriolis) couplings on the coherent polarization anisotropy are theoretically studied in a time-resolved two-photon ionization of a symmetric top molecule. This polarization anisotropy originates from a coherent excitation of the resonant rovibronic molecular eigenstates (rovibronic coherence) whose zeroth order states are mixed through the Coriolis coupling. Expressions for the time-dependent degree of polarization after the coherent excitation of the rovibronic states produced by the Coriolis coupling are derived as a function of the delay time in the pump–probe two-photon ionization. Model calculations of the time-dependent degree of polarization as well as the probabilities of the two-photon ionization are performed to demonstrate the Coriolis coupling effects in the low excess energy regions of the resonant intermediate state. It is shown that oscillatory behaviors in the time-dependent degree of polarization should be observed as a result of the creation of the rovibronic coherence. It is demonstrated that oscillations of the degree of polarization involve both contribution of the purely rotational J-coherence and that of the rovibronic coherence in the resonant manifold when the rotational branches are coherently excited and the characteristic rotation–vibration interaction energy is larger than a typical free rotational energy under jet-cooled condition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.452986
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  • 9
    Electronic Resource
    Electronic Resource
    Non-Markoffian theory of quantum beats in molecular fluorescence (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 84 (1986), S. 2112-2119 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We develop a theory of quantum beats in molecular fluorescence taking into account collision effects (such as pure dephasing due to elastic collision) without invoking the Markoff approximation. Model calculations of the time dependent fluorescence from molecules with two excited levels are performed in order to see how the non-Markoffian character in the collision process exerts influence upon the quantum beat pattern. It is suggested that if the pure dephasing between the excited states is a Markoffian "the degree of modulation of the beats'' decreases exponentially with time; if it is in the static limit the degree of modulation of the beats decreases as a Gaussian function (the non-Markoffian behavior in the quantum beats). A given case can be classified as either Markoffian or non-Markoffian, depending on the relative magnitudes of the collision duration time τc, the beat frequency ω, and the coupling strength v which is characteristic of the pure dephasing process. The Markoff approximation holds only if the condition ω〈v〈1/τc is satisfied; the non-Markoffian behavior appears in the quantum beat pattern when ω〉v, even if v2τ2c〈1 .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450422
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  • 10
    Electronic Resource
    Electronic Resource
    Theory of vibrational predissociation of van der Waals complex in the adiabatic approximation model (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 7106-7116 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A theory of the vibrational predissociation (VPD) of linear triatomic van der Waals (vdW) complexes in the adiabatic approximation model is developed aiming to evaluate the VPD rates from higher quantum states as well as the lowest one of the initially excited intramolecular vibrational mode. The adiabatic wave functions of the high frequency intramolecular mode and the adiabatic potential curves are constructed from a Morse-type interaction potential between the two neighboring atoms of the vdW bond. Using Fermi's Golden Rule, expressions for the rate of the VPD are derived both in the Condon approximation and in the non-Condon scheme. Important contribution of the non-Condon scheme in the adiabatic approximation model is demonstrated by performing model calculations of the VPD rate constants of I2X vdW complexes. The magnitudes of the rate constant in the Condon approximation are smaller than those in the non-Condon scheme by about one to two orders. It is shown that there is a good correspondence in the vibrational quantum number dependence between the treatment in the adiabatic approximation model and that in the scattering theory based on the zero-order diabatic basis set derived by Beswick and Jortner, and that the magnitudes of the vibrational predissociation rate constant calculated by them exist between those in the Condon approximation and in the non-Condon scheme. An approximate expression for the potential displacements between two adiabatic potentials and that for the intramolecular frequency shifts are also derived.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451397
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