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151.
We report the identification of the vacancy-hydrogen complex in single crystal diamond synthesized by chemical vapor deposition. The S=1 defect is observed by electron paramagnetic resonance in the negative charge state. The hydrogen atom is bonded to one of the carbon atoms neighboring the vacancy. Unlike the analogous defect in silicon, no symmetry lowering reconstruction occurs between the three remaining carbon dangling orbitals. The very small measured hydrogen hyperfine interaction is explained by dipolar coupling between the hydrogen and the unpaired electron probability density delocalized on the three equivalent carbon neighbors. 相似文献
152.
We report the identification of the nitrogen-vacancy-hydrogen complex in a freestanding nitrogen-doped isotopically engineered single crystal diamond synthesized by chemical vapor deposition. The hydrogen atom is located in the vacancy of a nearest-neighbor nitrogen-vacancy defect and appears to be bonded to the nitrogen atom maintaining the trigonal symmetry of the center. The defect is observed by electron paramagnetic resonance in the negative charge state in samples containing a suitable electron donor (e.g., substitutional nitrogen N(0)(S)). 相似文献
153.
The relatively large differences in De and Re obtained at the STO-3G level for hydrogen bonded dimers of water, methanol and dimethyl ether, and which correlate monotonically with atomic charges, are strongly attenuated with extended basis sets, and relationships among De,Re, and electron populations are reversed. Ratios of DeRe products for pairs of proton donors (acceptors) with a common acceptor (donor), however, are constant for a given basis set. 相似文献
154.
The continuum γ-rays following the reaction 166Er(α, 2n)168Yb have been studied at bombarding energies of 21, 27 and 36 MeV. The shape of the statistical γ-rays below 1 MeV was deduced. A low energy bump at ~300 keV was observed. This may arise from transitions along bands at and above the pairing gap. 相似文献
155.
156.
N.L. Allinger B.J. Gorden M.G. Newton L. Norskov-Lauritsen S. Profeta 《Tetrahedron》1982,38(19):2905-2909
The crystal structure of the title compound was determined by X-ray crystallography and solved by direct methods; the molecule has C2h symmetry. The carbon atoms are arranged in a diamondoid lattice, but not of the rectangular type that might have been expected. The dipole moment for the conformation found in the crystal is zero, while the observed dipole moment of the compound in solution is 2.78 D. Molecular mechanics calculations were carried out on several of the large number of possible conformation. Of those studied, the conformation found in the crystal had the lowest energy. 相似文献
157.
158.
A set of racemic 7-substituted 8-oxa-1-azabicyclo[4.3.0]nonanes have been prepared and configurational and conformational assignments made on the basis of the value of the geminal coupling constants for the C9 methylene protons. The limitations of the Bohlmann infrared criterion in studying the conformations of these compounds is discussed. 相似文献
159.
160.
Atomic and molecular electronic stopping powers for medium energy protons (≈ 10 keV-10 MeV) have been calculated using the binary-encounter approximation in conjunction with (1) either an energy or maximum impact parameter cut-off based on minimum excitation energies; and (2) ab initio electronic speed distributions. The maximum impact parameter approach yields good agreement with experiment for inert gases and closed-shell polyatomic molecules comprised of first-row atoms. 相似文献