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We extend the full-potential projector-augmented-wave method beyond the frozen core approximation, i.e., include the self-consistent optimization of the core charge density, in such a manner that the valence wave functions remain orthogonal to the core. The method consists of an on-the-fly repseudization of the all-electron problem, solving for the self-consistent core charge density within a spherical approximation. The key ideas in our procedure are to keep the projector functions fixed throughout the electronic minimization and to derive the new pseudopartial waves from these original projector functions, at each step of the electronic minimization procedure. Results of relaxed core calculations for atomic interconfigurational energies, structural energy differences between bulk phases of Fe, atomization energies of a subset of Pople's G2-1 set, and the Rh 3d surface core level shifts for the (log3 x log3)-Rh(111) surface at 1/3 CO coverage are presented. 相似文献
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For the 0–1 knapsack problem with equality constraint a partitioning procedure is introduced which focuses on the core of the problem. The purpose of the procedure is to reduce the required preliminary sorting for large problem instances. Computational results are presented for an improved heuristic as well as for a complete (exact) algorithm showing the success of the core approach. Test problems of size up to 15–000 objects are solved within 400–ms on a standard personal computer, that is, within the time that is needed for sorting the profit-weight ratios. The core algorithm reduces the solution times by a factor of up to four for large problem instances. 相似文献
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Abbott T Akiba Y Alburger D Beavis D Betts RR Birstein L Bloomer MA Bond PD Chasman C Chu YY Cole BA Costales JB Crawford HJ Cumming JB Debbe R Duek E Engelage J Fung SY Grodzins L Gushue S Hamagaki H Hansen O Hayashi S Homma S Huang HZ Ikeda Y Katcoff S Kaufman S Kimura K Kitamura K Kurita K Ledoux RJ Levine MJ Miake Y Morse RJ Nagamiya S Olness J Parsons CG Remsberg LP Sarabura M Shor A Stankus P Steadman SG Stephans GS Sugitate T Tannenbaum MJ Torikoshi M van Dijk JH Videbaek F Vient M 《Physical review letters》1990,64(8):847-850
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Verheijen JC Deiman BA Yeheskiely E van Der Marel GA van Boom JH 《Angewandte Chemie (International ed. in English)》2000,39(2):369-372
The introduction of a urea bond linking a protected diethylenetriamine (DETA) unit and the terminal amino group of a resin-bound peptide nucleic acid (PNA) decamer gave access to a PNA - DETA adduct (shown here), which hydrolyzed the target 25-mer RNA rapidly and sequence specifically. 相似文献
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Marsman AW van Poecke BL Jenneskens LW Spek AL Lutz ET van der Maas JH 《Organic & biomolecular chemistry》2005,3(8):1402-1409
From a saturated C6H6 solution of racemic 4-(tetrahydro-4H-thiopyran-1-oxide-4-ylidene)-cyclohexanone oxime [1(1-R/1-S)] the co-crystal is crystallized. Single crystal X-ray analysis showed that (1)4.C6H6 (P1 space group) in the solid-state consists of enantiomorphous, non-covalent polymer-like chains that contain, in an alternating fashion, the crystallographically independent enantiomers 1-R and 1-R' or 1-S and 1-S', respectively. Within each chain the enantiomers are linked by 'head-to-tail' intermolecular oxime-sulfoxide hydrogen bonding [D(2) motif]. Neighbouring chains consist of enantiomers with opposite configuration and possess opposite molecular 'head-to-tail' alignments. The enantiomorphous chains are interconnected by weak intermolecular C-HO hydrogen bonds involving centrosymmetric C-Hoxime [R(12)] and C-Hsulfoxide [R(8)] motifs between the 1-R and 1-S molecules in neighbouring chains; a nearly planar two-dimensional hydrogen bonding network motif is obtained. In the crystallographic direction [1 0 0] the layers stack in such a fashion that chains occupying successive layers with an identical 'head-to-tail' alignment are positioned on top of each other. Concomitantly, channels with areas of ca. 25 Angstroms(2) are obtained, which are occupied by C6H6 solvent molecules. A comparison of the IR and Raman spectra of with those obtained for native 1 that does not contain C6H6, indicates that intermolecular oxime-sulfoxide hydrogen bonding [D(2) motif] also occurs for native 1 in the solid-state. 相似文献
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