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81.
The possibility of explicit pionic degrees of freedom in atomic nuclei and their association with pionic reactions involving fragment emission is discussed. Although no present direct evidence for such degrees of freedom is available they could be searched for in doorway states — other than the anticipated N1 doorway — in the excitation function in the pion-induced partial reaction cross sections. Such a search is underway. A framework is discussed in terms of which such new pion doorways might be described. 相似文献
82.
An analysis is made of the device of forced vibrations to reduce the difficult large amplitude TDHF (time-dependent Hartree-Fock) problem to a simpler static problem. It is shown that cranking is a perfectly valid technique if the cranking field is defined by the criterion that the constrained static wave function be identical at a given instant of time to the freely oscillating TDHF wave function. On the basis of this criterion an exact general expression is derived for the cranking field and adiabatic and non-adiabatic cranking models are proposed as practical means of solving the large amplitude TDHF equations and calculating energy surfaces for fission and heavy ion reactions. The non-adiabatic model, which is favoured, corresponds to cranking the nucleus to move always in the direction of a local decoupled “normal mode” calculated from its unconstrained time-dependent equations of motion. The familiar Belyaev cranking model and the Baranger-Kumar model are discussed in the context of the new formalism. 相似文献
83.
The traditional Hartree method of solving the Hartree-Fock equations, by repeated diagonalization and recalculation of the single-particle Hamiltonian, is expressed in terms of repeated unitary transformations and shown to be applicable to the general SCF (self-consistent field) equations. The necessary and sufficient conditions for convergence to a unique local SCF solution are derived and it is shown that only a small class of solutions are obtainable by this method. 相似文献
84.
New X-ray photoemission spectroscopy data and high resolution electron scattering spectroscopy data are presented which indicate that a peroxide-like model of the oxygen chemisorption on silicon surface is correct. These results are discussed in light of a recent double-bonded oxygen atom model due to Ludeke and Koma. 相似文献
85.
86.
Photoenols derived from 2-benzyl- and 2-ethylbenzophenone have been trapped by maleic anhydride, methyl fumarate and phenyl fumarate. Stereochemical determinations of the single adduct obtained in each case in high yield have shown unequivocally that the Diels-Alder addition proceeds from the (E,E)-dienol by an endo approach, an interaction between the dienol hydroxylic group and one of the dienophile carbonyl group being strongly determinant. These results do not eliminate the possibility that an unreactive (Z,E)-dienol be formed during the photochemical step. 相似文献
87.
88.
DeMarco B Ben-Kish A Leibfried D Meyer V Rowe M Jelenković BM Itano WM Britton J Langer C Rosenband T Wineland DJ 《Physical review letters》2002,89(26):267901
We report the experimental demonstration of a controlled-NOT (CNOT) quantum logic gate between motional and internal-state qubits of a single ion where, as opposed to previously demonstrated gates, the conditional dynamics depends on the extent of the ion's wave packet. Advantages of this CNOT gate over one demonstrated previously are its immunity from Stark shifts due to off-resonant couplings and the fact that an auxiliary internal level is not required. We characterize the gate logic through measurements of the postgate ion state populations for both logic basis and superposition input states, and we demonstrate the gate coherence via an interferometric measurement. 相似文献
89.
Dr. Chinmay Y. Majmudar Dr. Jonas W. Højfeldt Carl J. Arevang Dr. William C. Pomerantz Jessica K. Gagnon Pamela J. Schultz Laura C. Cesa Conor H. Doss Dr. Steven P. Rowe Victor Vásquez Prof. Dr. Giselle Tamayo‐Castillo Prof. Dr. Tomasz Cierpicki Prof. Dr. Charles L. Brooks III Prof. Dr. David H. Sherman Prof. Dr. Anna K. Mapp 《Angewandte Chemie (International ed. in English)》2012,51(45):11258-11262
90.