The inelastic depolarized light-scattering spectrum of the endohedral metallofullerene Li+ @ C60 is calculated for frequency shifts up to 1000 cm-1. In this species the motion of the charged inclusion within the bucky...
The inelastic depolarized light-scattering spectrum of the endohedral metallofullerene Li+ @ C60 is calculated for frequency shifts up to 1000 cm-1. In this species the motion of the charged inclusion within the buckyball cage generates an induced anisotropic polarizability through an interesting mechanism involving the hyperpolarizability B. The resulting Raman spectrum is quite intense. At room temperature, hot bands contribute significantly to the scattering.
The infrared spectrum of the endohedral metallofullerene Li+ @ C60 is calculated. Vibrational and rotational motion of the charged inclusion leads to the emission and absorption of radiation. Our calculations assume t...
The infrared spectrum of the endohedral metallofullerene Li+ @ C60 is calculated. Vibrational and rotational motion of the charged inclusion leads to the emission and absorption of radiation. Our calculations assume this motion is governed by the intramolecular ''reflected Morse'' potential of Dunlap, Ballester and Schmidt. The predicted pure rotation band peaks near 40 cm-1. The fundamental vibration-rotation band at 350 cm-1 exhibits unusual band-head structure. Both bands are intense. The first overtone band at 700 cm-1 is also studied. Rotational structure is well resolved in all three bands;at room temperature, hot bands contribute significantly.
We compute the far-infrared absorption spectrum of the endohedral metallofullerene K+ @ C60. This arises from the vibrational and rotational motion of the potassium ion about its equilibrium position at the center of ...
We compute the far-infrared absorption spectrum of the endohedral metallofullerene K+ @ C60. This arises from the vibrational and rotational motion of the potassium ion about its equilibrium position at the center of the buckyball cage. The spectrum is quite unusual. Although the permanent dipole moment of the complex is zero, absorption is very intense. The spectrum contains a pure rotation band, which peaks near 55 cm-1 at 25-degrees-C. There is also a fundamental vibration-rotation band, consisting of a strong P-branch at 70 cm-1, overlapping the rotational band, and a much weaker R-branch at 180 cm-1. Line-spacing is strongly dependent on the rotational quantum number. Hot bands contribute significantly to the intensity. We include a discussion of dipolar shielding effects.
We report explicit results for the zero-field correlation length, xi(T;L), of a spherical-model ferromagnet confined to geometry L(d-d') x infinity(d') (d > 2, d' less-than-or-equal-to 2) and subjected ...
We report explicit results for the zero-field correlation length, xi(T;L), of a spherical-model ferromagnet confined to geometry L(d-d') x infinity(d') (d > 2, d' less-than-or-equal-to 2) and subjected to 'twisted' boundary conditions. In the region of first-order phase transition ( T< T(c)), xi under 'twisted' boundary conditions obeys the same scaling law as under periodic boundary conditions, though with a different amplitude. In the 'core' region (T congruent-to T(c)), the scaling behaviour changes radically as one moves from one set of boundary conditions to the other affected greatly by the 'pinning' of the ground-state wavevector k0 of the system.
Making use of the Poisson summation formula in m dimensions, a class of phase-modulated lattice sums is evaluated analytically. The resulting formulas provide a broad generalization of the results reported previously ...
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Making use of the Poisson summation formula in m dimensions, a class of phase-modulated lattice sums is evaluated analytically. The resulting formulas provide a broad generalization of the results reported previously and are of considerable use in the analysis of finite-size effects in systems undergoing phase transitions, especially when the boundary conditions imposed are other than periodic.
Adhesive and transparent polymer blend electrolytes were synthesized by the free radical polymerization of methyl methacrylate (MMA) in poly (propylene glycol) (PPG) complexed with lithium triflate (LiCF3SO3). Polymer...
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Adhesive and transparent polymer blend electrolytes were synthesized by the free radical polymerization of methyl methacrylate (MMA) in poly (propylene glycol) (PPG) complexed with lithium triflate (LiCF3SO3). Polymer electrolytes with differing PPG molecular weights, PMMA composition, and O/Li ratios were prepared. The physical characteristics of the polymer blend electrolytes were found to depend on the PPG molecular weight, salt concentration and PMMA content. SEM studies indicated the polymer blends to have a phase separated morphology. The salt, LiCF3SO3, was found to act as an emulsifier in stabilizing the two phase microstructure of the blends.
Scanning micro-PIXE is employed in conjunction with backscatter electron imaging and cathodoluminescence to study oscillatory zoning of minor and trace elements in natural and synthetic minerals. The scanning proton m...
Scanning micro-PIXE is employed in conjunction with backscatter electron imaging and cathodoluminescence to study oscillatory zoning of minor and trace elements in natural and synthetic minerals. The scanning proton microprobe (SPM) is also used to study surface features on individual mineral grains.
Angular distributions of L3 x-ray transitions, including electric-dipole-forbidden ones, were measured for 1-, 2-, and 3-MeV proton impact on a thorium target, where the excitation and detection systems were cylindric...
Angular distributions of L3 x-ray transitions, including electric-dipole-forbidden ones, were measured for 1-, 2-, and 3-MeV proton impact on a thorium target, where the excitation and detection systems were cylindrically symmetric. A sophisticated spectrum-analysis technique was applied, where both the Lorentzian broadening of the transitions and the Si(Li) detector response function with various tailing features were taken into account. The anisotropy-parameter ratios are expected to be independent of the ionization process, and to be characteristic of the x-ray transitions in the independent-particle model. The ratios of the anisotropy parameters of the electric-dipole-allowed transitions were in disagreement with this expectation, even when the higher-order multipole contributions were taken into account. These results follow the same trend as earlier angular distribution and angular correlation measurements. Additionally, the electric-dipole-forbidden LtL3M2) and Ls(L3M3) transitions had a P4(cos(θ)) term, which is not expected within the framework of the single-particle-model predictions. Possible causes for this discrepancy are explored.
Infrared absorption spectra from metastable helium atoms (2s 3S, 2s 1S) and molecules (a Σu+3) were previously acquired by irradiating dense helium gas near 4.2 K with a pulsed proton beam [R. L. Brooks, J. L. Hunt, ...
Infrared absorption spectra from metastable helium atoms (2s 3S, 2s 1S) and molecules (a Σu+3) were previously acquired by irradiating dense helium gas near 4.2 K with a pulsed proton beam [R. L. Brooks, J. L. Hunt, and D. W. Tokaryk, J. Chem. Phys. 91, 7408 (1989)]. The molecular spectrum was unusual because the observed rovibrational distribution within the a Σu+3 state was far from thermal equilibrium. Three different rovibrational groups were observed: (i) v=0, N=1 (‘‘thermal’’ molecules); (ii) v=0, 9≤N≤21 (rotationally excited molecules); and (iii) 10≤v≤12, N=1 (vibrationally excited molecules). In this work, the time evolutions of members of these three molecular populations were studied both during irradiation and in the subsequent afterglow. In addition, the evolution of the 2s 3S–2p 3P atomic line was investigated. This study quantitatively explores the reaction dynamics of the metastable molecule in the gas phase near 4.2 K. Gas pressures between 100 and 750 Torr were used. Time-resolved data were taken with a transient-digitizer system and summed for several thousand cycles of the pulsed proton beam. The absorption measurements were converted to time-resolved number densities with the aid of theoretical transition moments. The analysis required that the data be fit to the solutions of sets of coupled differential equations with a nonlinear least-squares-fit routine. The results provide insight into the complicated reactions involved in generating the unusual molecular distribution and into the reactions between the metastable molecules, metastable atoms, and the background helium gas.
Angular correlations between Kα1 x rays and subsequent L3 x-ray transitions were measured using a Pa233 radionuclide source and high-resolution x-ray detectors. The results provide separately the values of A22(Kα1−L...
Angular correlations between Kα1 x rays and subsequent L3 x-ray transitions were measured using a Pa233 radionuclide source and high-resolution x-ray detectors. The results provide separately the values of A22(Kα1−Lα1) and A22(Kα1−Lα2) as opposed to the compound quantity A22(Kα1−Lα). For the Ll and Lα2 transitions, the A22 values agreed closely with those based upon theoretical (Hartree-Fock) E1 and M2 transition rates. For the less intense Lβ6 and Lβ2,15 transitions, agreement was also observed, although within larger uncertainties. In contrast, the value of A22(Kα1−Lα1) was 0.085±0.007, which is somewhat larger than the predicted value of 0.073. Possible causes for this discrepancy are explored.
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