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141.
A LO-phonon replica of the first order Raman spectrum of (GaxIn1-xP and Ga(As1-xPx) has been observed for the first time. The experiment shows strong resonance with varying incoming photon energy which only appears in the presence of alloying and disorder. The results can only be understood if the relevant resonant intermediate state is a localized sharp exciton strongly interacting with the LO-phonon system, i.e. a localized exciton-phonon complex. Under those conditions, a simple model yields a ratio of the two-phonon to one-phonon intensities which is given by straightforward Franck-Condon overlaps. 相似文献
142.
Surface and structural properties of chromium-zirconium mixed and Sn(II)doped hydrous oxide gels have been compared with chromium oxide hydrate gel by the use of thermal analysis, IR spectroscopy, X-ray diffraction, electron microscopy and magnetic measurements. The mixed and doped oxide gels were found to have a hexagonal close packed stacking of O, OH and H2O ligands with chromium ions distributed in octahedral sites with little degree of order among them. The microstructure of the gels are characterized by the presence of large aggregates of chromium hydroxides, fine granular sheets due to HCrO2 phase and Cr(OH)3 microcrystallites. Magnetic susceptibility measurements indicate anti-ferromagnetic behaviour of these gels. 相似文献
143.
The blocking and deblocking sequence pertaining to the α,β-unsaturated methylene γ-lactone unit of costunolide is described. Utilizing this approach a simple and practical synthesis of dehydrosaussurea lactone is reported. 相似文献
144.
The study of 2699 Å electronic band system of chlorobenzene has been extended to extract out all the six b1 and three a2 modes in both the ground state (eA1) and the electronically excited first singlet state (eB2). The procedure of the extraction of these modes on the basis of observed sequences, cross-sequences, and overtones has especially been elaborated. Strong Fermi interaction has been observed between the vibrational level ν′6b and combination level ν′16a + ν′16b in eB2 state. The uniqueness of the assignments of the modes has been critically discussed. 相似文献
145.
R. N. Jain 《Proceedings Mathematical Sciences》1970,71(5):215-218
146.
Dielectric behaviour of MgO, CaO, SrO, BaO, SrS and BaS has been studied on the basis of the shell model and the exchange charge shell model. Values of polarizabilities and effective charge parameter calculated from the two models are compared with experimental data. 相似文献
147.
The cross sections for the 16O(α, 2α) reaction have been calculated in the distorted wave impulse approximation. The influence of the optical potentials in the incident and final channels on the energy sharing distribution and the spectroscopic factors has been investigated. Optical potentials with small imaginary content are shown to fit both elastic scattering and the experimental data well and give a spectroscopic factor of 1.1; the contribution from the nuclear interior broadens the energy sharing distributions, in agreement with observations. 相似文献
148.
The spherulitic growth data that exist in the literature for a wide diversity of polymers have been analyzed according to various possible nucleation mechanisms. It is demonstrated that, if allowed a reasonable choice for the equilibrium melting temperature, no unbiased selection of a unique nucleation process can be made. Moreover, a set of universal parameters exists for each of the allowable nucleation processes which enables the data to be represented by a single straight line which encompasses all the polymers. The only quantities specific to a given polymer are the equilibrium melting temperature and the activation energy for transport. The magnitude of the latter quantity is shown to be dependent on the glass temperature of the polymer. 相似文献
149.
The time-differential perturbed angular correlation (TDPAC) experiments involving the 133–482 keV γ-γ cascade in181Ta have been performed in the presence of an external magnetic field along the quantization axis to measure the hyperfine magnetic field experienced by181Ta nuclei at the Hf site in the pseudobinary compounds HfFe2?xSix with x=0.1 and x=0.3. The hyperfine magnetic fields measured at 298 K are Hhf=133.1±12.0 kG in the cubic (C15) Laves phase compound HfFe1.9Si0.1 and Hhf=76.8±7.0 kG in the hexagonal (C14) Laves phase compound HfFe1.7Si0.3. The measured hyperfine fields are discussed within the framework of the Campbell-Blandin model. 相似文献
150.
IR absorption in p-type melt grown Pb0.97Sn0.03Se crystals is reported. The results for the room temperature absorption coefficient (α) in the wavelength region 2–15 μm are analysed. The indirect absorption edge is found to be at 0.26 eV for this ternary alloy. In the longwavelength region α is found to be proportional to λ2, in agreement with the classical free carrier absorption expression. The conductivity effective mass of holes is found to be 0.067 m0 at 300°K. 相似文献