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The a-type N = 1 ← 0,2 ← 1, and 3 ← 2 and the b-type 111 ← 202, 212 ← 303, 313 ← 404, 606 ← 515, and 707 ← 616 transitions, 14 in total, of the DO2 free radical in the ground vibronic state were observed by microwave spectroscopy in the frequency region up to 200 GHz. The DO2 radical was generated in a free-space absorption cell by a DC discharge in a mixture of CH3OD and O2. From the observed spectra the rotational constants, centrifugal distortion constants, spin-rotation coupling constants, and magnetic hyperfine coupling constants were determined with good precision. The hyperfine coupling constants of DO2 were determined by the present work for the first time. A comparison of the in-plane components of the dipole-dipole interaction tensor of DO2 with those of HO2 made it possible to determine the off-diagonal component Tab, and thus the principal values and the principal axes of the tensor. 相似文献
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Two strong laser-excited fluorescence systems are observed in rare gas matrices containing Sn. Evidence is presented suggesting assignment of the emission to Sn2. The fluorescence spectrum provides a value of 188 cm?1 for the ground-state vibrational frequency of this diatomic molecule. 相似文献
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B. Houlier 《Solid State Communications》1975,17(3):263-266
X-irradiation at 80°K leads to the formation of VK centres and, in addition, perturbed F centres in the case of BaCl2:K+. The VK centres spectra exhibit a superhyperfine structure. A warming to 130°K of crystals X-irradiated at 80°K causes the VK centres to be perturbed, and besides leads to the formation of (AgCl4)2? complexes in BaCl2:Ag+. 相似文献
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A single-crystal TlGaSe2 doped by paramagnetic Fe ions has been studied at room temperature by electron paramagnetic resonance (EPR) technique. The fine structure of EPR spectra of paramagnetic Fe3+ ions was observed. The spectra were interpreted to correspond to the transitions among spin multiplet (S=5/2, L=0) of Fe3+ ion, which are splitted by the local ligand crystal field (CF) of orthorhombic symmetry. Four equivalent Fe3+ centers have been observed in the EPR spectra and the local symmetry of crystal field at the Fe3+ site and CF parameters were determined. Experimental results indicate that the Fe ions substitute Ga at the center of GaSe4 tetrahedrons, and the rhombic distortion of the CF is caused by the Tl ions located in the trigonal cavities between the tetrahedral complexes. 相似文献
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Total internal partition sums are calculated in the product approximation at temperatures up to 6000 K for the asymptotic asymmetric-top SiO2 molecule.The rotational partition function and the vibrational partition function are calculated with the rigid-top model and in the harmonic oscillator approximation,respectively.Our values of the total internal partition sums are consistent with the calculated value in the Gaussian program within 0.137% at 296 K.Using the calculated partition functions and the rotationless transition dipole moment squared as a constant,we calculate the line intensities of 001-000 band of SiO2 at normal,medium and high temperatures.Simulated spectra of the 001-000 band of the asymptotic asymmetric-top SiO2 molecule at 2000,5000 and 6000 K are also obtained. 相似文献
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In this paper, we give an alternative suggestion that both the observed optical and electron paramagnetic resonance (EPR) spectra of Yttrium oxide (Y2O3):V3+ are attributed to V3+ ions at the S6 site of Y2O3. This suggestion is different from the opinion in the previous paper that the optical and EPR spectra are attributed to V3+ ions at the C2 and S6 sites, respectively. From the suggestion, the optical band positions and spin-Hamiltonian parameters are calculated by diagonalizing the complete energy matrix for 3d2 ions in trigonal symmetry. The results are in good agreement with the experimental values, suggesting that both the observed optical and EPR spectra in Y2O3:V3+ may be due to V3+ at S6 site of Y2O3 crystal. 相似文献
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TlGaS2 single crystal doped by paramagnetic Fe3+ ions has been studied by electron paramagnetic resonance (EPR) technique. The fine structure of EPR spectra of paramagnetic Fe3+ ions was observed. The spectra reveal a nearly orthorhombic symmetry of the crystal field (CF) on the Fe3+ ions. Two groups each consisting of four equivalent Fe3+ centers were observed in the EPR spectra. The local symmetry of the crystal field on the Fe3+ centers and CF parameters were determined. Experimental results indicate that the Fe ions substitute Ga at the center of the GaS4 tetrahedrons. The rhombic distortion of the sulfur ligand CF is attributed to the effect of Tl ions located in the trigonal cavities between the tetrahedral complexes. The observed twinning of the resonance lines indicates a presence of two non-equivalent positions of Tl ions that confirms their zigzag alignment in the TlGaS2 crystal structure. 相似文献
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An EPR study of tetravalent vanadium centers created by room temperature X-irradiation in CaF2 and SrF2 is presented. The production efficiency of these centers is enhanced by previous annealing of the samples at 1000 K in air. The symmetry of V4+ ions is tetragonal and its EPR spectrum can be described by an axial spin Hamiltonian including a Zeeman and hyperfine term with and (corresponding to 51V nuclei). The following values for the spin Hamiltonian parameters are obtained g∥ = 1.947 ± 0.002, g⊥ = 1.935 ± 0.005, A∥ = 500 ± 5 MHz, A⊥ = 150 ± 10 MHz in the case of SrF2 and g∥ = 1.945 ± 0.002, A∥ = 505 ± 5 MHz and A⊥ < 200 MHz, in the case of CaF2. A model for the center including an interstitial O2? ion is tentatively proposed. 相似文献
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Cheng-Gang Li Mei-Ling Duan Ya-Ru Zhao 《Journal of Physics and Chemistry of Solids》2010,71(11):1599-1602
The local lattice structure and EPR parameters (D, g‖, g⊥) have been studied systematically on the basis of the complete energy matrix for a d3 configuration ion in a trigonal ligand field. By simulating the calculated optical and EPR spectra data to the experimental results, the local distortion parameters (ΔR, Δθ) are determined for V2+ ions in CdCl2 and CsMgCl3 crystals, respectively. The results show that the local lattice structure of CdCl2:V2+ system exhibits a compression distortion (ΔR=−0.0868 Å) while that of CsMgCl3:V2+ system exists an elongation distortion (ΔR=0.0165 Å). The different distortion may be ascribed to the fact that the radius of V2+ ion is smaller than that of Cd2+ ion or larger than that of Mg2+ ion. Moreover, the relationships between EPR parameter D and local structure parameters (R, θ) as well as the orbital reduction factor k and g‐factors (g‖, g⊥) are discussed. 相似文献
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Reflectivity spectra of CuInSe2, CuInTe2 and CuGaTe2 are measured in the photon energy range from 2 to 9 eV. All compounds exhibit nearly the same reflectivity structures, and a comparison with measurements on the other Cu-III-VI2 semiconductors shows that the band structures of all Cu-III-VI2 compounds should be very similar except the energy range near the fundamental edge. 相似文献
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In this work, two d-d transition spectra and four EPR parameters g∥, g⊥, A∥, A⊥ of K2PdCl4/Cu2+ are uniformly interpreted based on Zhao's crystal-field model. The calculation result is in good agreement with the experiment findings. The ligand spin-orbit coupling is neglected on the calculation, which is consistent with the ab initio result by Hillier et al. [J. Am. Chem. Soc. 98 (1976) 95] 相似文献
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The EPR powder spectra of spinel solid solutions CoxZn1-xRh2O4 (x ? 0.10) have been studied in the temperature range 6–77 K. The spectra show that Co2+ ions occupy distorted tetrahedral sites. As the cobalt concentration increases, the spectrum of the isolated ions is gradually replaced by a strong absorption produced by antiferromagnetic exchange coupled clusters of Co2+ ions. 相似文献
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Rui-Peng Chai Cai-Xia Zhang Hui Wang 《Journal of Physics and Chemistry of Solids》2008,69(7):1848-1854
For a d8 configuration ion, the 45×45 complete energy matrix, which contains the electron-electron repulsion interaction, the ligand-field interaction, the spin-orbit coupling interaction as well as the Zeeman interaction, has been established. By diagonalizing the complete energy matrix, the local lattice structure, EPR parameters (D, g//, g⊥) and optical absorption spectra for Ni2+ ions doped in LiNbO3 and Al2O3 have been investigated. The local structure distortion parameters ΔR, Δθ1 and Δθ2 are determined for LiNbO3:Ni2+ and Al2O3:Ni2+ systems, simultaneously. These results show that local structure of (NiO6)10− cluster exhibits an elongation distortion in both LiNbO3:Ni2+ and Al2O3:Ni2+ systems, in spite of the different reasons of the elongation in both systems. In addition, we have found that the orbit reduction effect is very important to understand the anisotropic g-factors for Ni2+ ions doped in LiNbO3 and Al2O3 crystals. 相似文献
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HeI and Mg Kα1,2 valence band photoelectron spectra of polycrystalline samples of NbO2, MoO2 and RuO2 are reported. A marked increase is observed in the intensity of the metal 4d structure, relative to that due to oxygen 2p electrons, on changing from X-ray to UV excitation. The superior resolution of the 4d signals in the HeI spectra reveals the presence of the Fermi edge in the metallic oxides MoO2 and RuO2. In addition, the HeI spectrum of MoO2 shows a splitting of the metal 4d signal, confirming established ideas concerning the electronic structure of such materials. 相似文献
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Three rotational transitions, 110 ← 101, 220 ← 211, and 330 ← 321, of the PH2 radical in the ground vibronic state were observed in the mm-wave region, by using a source-frequency modulation spectrometer with a 1-m-long free space cell. The PH2 radical was generated directly in the cell by glow discharge in a mixture of phosphine and oxygen. Thirty four fine and hyperfine components were measured for the three transitions. An analysis of the observed spectra, combined with far-infrared and mid-infrared laser magnetic resonance spectra and laser-induced fluorescence spectra obtained by other works, improved the rotational and spin-rotation interaction constants in precision. The observed hyperfine structure gave the magnetic hyperfine coupling constants for both P and H nuclei and also the P nuclear spin-rotation interaction constants. 相似文献
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V. Riede H. Sobotta H. Neumann Hoang Xuan Nguyen W. Möller G. Kühn 《Solid State Communications》1978,28(6):449-454
The lattice vibration spectra of CuInSe2 and CuGaTe2 were investigated by infrared reflectivity measurements in the wavenumber range from 55 to 5000 cm?1. The mode energies were determined by a Kramers-Kronig analysis of the spectra. The results are compared with existing measurements and some general trends in the phonon energies of the I-III-VI2 compounds are discussed. 相似文献
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The Raman spectra of single crystals of CrO2 and MoO2 have been studied from 77°K to 500°K for a comparison with the heavily damped phonon features in metallic VO2. The spectrum of MoO2 is very similar to that of monoclinic VO2 whereas CrO2 exhibits phonon spectra similar to rutile with no appreciable change at the ferromagnetic c curie temperature. The results are discussed with respect to the various models proposed for the semiconductor-to-metal transition in VO2. 相似文献