The mechanism of acid-base catalysisSpringer Science and Business Media LLC - Tập 27 - Trang 615-619 - 1991
K. K. Kalninysh
New concepts of the mechanism of acid-base catalysis are developed, incorporating electron transfer in low-lying electronic excited states of the reagent-catalysts complex. In base catalysis, the base-catalyst lowers the ionization potential of one of the reagents, the proton and electron dnor, and thereby lowers the energy of the excited level. Acid catalysis consists in intensifying the electron...... hiện toàn bộ
Van der Waals Gaps in Sm1+x Ba2−x Cu3O y and Their Effect on SuperconductivitySpringer Science and Business Media LLC - Tập 38 Số 3 - Trang 162-167 - 2002
Nishchenko, M. M., Likhtorovich, S. P., Drozd, V. A., Nedil'ko, S. A., Baginskii, I. L.
We have used electron–positron annihilation to study superconducting cuprates Sm1+x Ba2−x Cu3O y . We have determined the average radii for oxygen ions in Sm1+x Ba2−x Cu3O y . Taking into account the ion coordinates and their radii, we have constructed a geometric model for the arrangement of copper and oxygen ions in CuO2 layers in the [b, c] plane, responsible for the superconductivity. From the...... hiện toàn bộ
Quantum dynamic calculation for gas-phase nucleophilic substitution (SN2) reactionsSpringer Science and Business Media LLC - - 1987
V. M. Ryaboi
According to experimental data, gas-phase SN2 reactions have low efficiency characterized by the ratio k(T)/kc, where kc is the collision rate constant. The energy profile of the reaction pathway is a double-well curve, and the top of the central barrier may be located either above or below the energy level of the reagents. Nonempirical calculations of the potential surfaces for SN2 reactions have...... hiện toàn bộ