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181.
182.
183.
Yasumitsu Matsuo Junko Hatori Yukihiko Yoshida Yutaka Ikedo Jun Sugiyama Seiichiro Ikehata 《Physics letters. A》2009,373(38):3470-3472
In order to clarify the mechanism of superprotonic conductivity (SPC) for the hydrogen-bonded compound CsHXO4 (X=S, Se), we have investigated the elastic properties of CsHXO4 with various transition temperatures (Tc), at which CsHXO4 exhibits a structural phase transition from a low-temperature monoclinic phase with low protonic conductivity (phase II) to a high-temperature SPC phase (phase I). It was found that, in CsHSxSe1 − xO4 (x=0–1), the transition temperature Tc decreases in proportion to the square of spontaneous strain b in the aII–bII plane of phase II. This result indicates that the spontaneous strain in the aII–bII plane plays an important role in the appearance of SPC in CsHXO4. Moreover, thermodynamic analyses suggest that proton migration in phase I is induced by the release of the strain energy. From these results, it is deduced that the phase transition temperature in CsHXO4 is determined by the competition between the kinetic energy of proton and the released-strain energy. 相似文献
184.
It is demonstrated that the fashions of the concentration-dependences of half-band widths are markedly different between the corresponding bands in i.r. absorption and Raman spectra when the i.r. absorption intensities of the bands are extremely large. On the other hand, when the i.r. intensities are not so great, the similar behaviour is observed for the changes in the half-band widths. In this study, these phenomena have been discussed in terms of the vibrational relaxation of resonance type and the local field effect. 相似文献
185.
Takeshi Wada Akira Mochizuki Seiichiro Higashiya Hiroyuki Tsuruoka Shun-ichi Kawahara Masahide Ishikawa Mitsuo Sekine 《Tetrahedron letters》2001,42(52):9215-9219
2-Azidodeoxyadenosine (7) was conveniently synthesized from deoxyguanosine (2) by use of a combined reagent of TMSN3–BuONO. The structure of the tautomer of the azido derivative was determined by 1H NMR. Reaction of 7 with iPr2NP(OEt)2 gave an intermediate 10 of the Staudinger reaction. Incorporation of 7 into a DNA 13mer resulted in a significant decrease of the Tm value of the DNA duplex upon hybridization with the complementary strand. The thermal stability was discussed based on the hydrogen bond energy and electrostatic repulsion. 相似文献
186.
The sensitization effect in the IR-F spectroscopy by addition of SF6 was investigated in case of acetone as a sample. We kept the partial pressure of acetone constant, varied that of SF6, and investigated the variations of the degree of sensitization. The experimental data shows that the degree of sensitization increases steeply and is saturated as the partial pressure of SF6 becomes higher. The results were examined in terms of the kinetics of the intra-and intermolecular energy transfer involved in the emission of infrared radiation in question. 相似文献
187.
In this report, we describe a new method for the synthesis of densely functionalized pyrroles. Reaction of mesoionic 1,3-oxazolium-5-olates with various S-ylides proceeds via nucleophilic addition followed by opening of the oxazole ring and subsequent cyclization to multisubstituted pyrroles bearing both a trifluoromethyl and alkyl(aryl)thio group at 3- and 4-positions. 相似文献
188.
We summarize explicitly correlated electronic structure theory in perspective of future work in the field. Earlier stages of approaches with different Ansätze in physics and chemistry are described. We then discuss recent advances focusing on explicitly correlated wave functions using cusp conditions. Removal of Coulomb singularities in terms of the rational generator is brought out from the viewpoint of many-body perturbation theory. On the basis of decomposition schemes for many-electron integrals in R12 and F12 methods, we further discuss the possibility of increasing the accuracy of molecular numerical integration and massively parallel calculations of explicitly correlated methods. 相似文献
189.
Yasumitsu Matsuo Yuya Shimizu Tomoaki Suzuki Seiichiro Ikehata 《Solid State Communications》2004,129(8):529-532
Measurements of the spin-lattice relaxation time, NMR absorption line and magnetization have been carried out on the Tl3H(SO4)2 crystal below 50 K. The anomaly at around 7 K was: (1) the spin-lattice relaxation times of 1H and 205Tl nuclei increase steeply with decreasing temperature below 7 K, (2) the NMR absorption lines below 7 K shift to the high-magnetic field side in comparison with that above 7 K, and (3) the 1H NMR line width exhibits a drastic increase of the line width with decreasing temperature below 7 K. These results indicate that the magnetic dipole fluctuation of the proton changes at 7 K. On the other hand, there are no remarkable anomalies of magnetic susceptibility at around 7 K. From these results it is deduced that the anomaly at around 7 K is caused by the change in quantum mechanical process of the proton from proton tunneling to zero-point vibration of hydrogen in the hydrogen bond with the decrease of temperature. 相似文献
190.
K. Nishimura S. Ohya T. Ohtsubo T. Izumikawa M. Sasaki I. Sato M. Suzuki J. Goto M. Tanigaki A. Taniguchi Y. Ohkubo Y. Kawase S. Muto 《Hyperfine Interactions》2004,159(1-4):239-243
Recent studies of hyperfine fields B
HF of Sr and Y in Fe are briefly reviewed. The B
HF value of Y in Ni is given by NMRON of 91mYNi. The nuclear magnetic moment of the ground state of 93Y is extracted from the β-ray detected NMRON of 93YFe. 相似文献