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Lahamer AS Mahurin SM Compton RN House D Laerdahl JK Lein M Schwerdtfeger P 《Physical review letters》2000,85(21):4470-4473
Mossbauer spectra for l and d enantiomers of the Fe(phen)3Sb2(C4H2O6)(2);8H(2)O complex are reported. Four independent experiments show a small but reproducible energy shift of the Fe-Mossbauer spectra for the two enantiomers of 0.004+/-0. 002 mm/sec ( 1.9x10(-10) eV). This exceedingly small energy difference is comparable to that predicted by the parity-violating energy difference (PVED) using a Z6.2 scaling law applied to low Z ( Z = 6) molecules. Theoretical calculations suggest that the PVED for the Fe(phen)2+3 moiety should be smaller than this estimate, however, PVED effects of the chiral antimony tartrates are not taken into account. 相似文献
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We show how to relate the full quantum dynamics of a spin-½ particle on \({\mathbb{R}^d}\) to a classical Hamiltonian dynamics on the enlarged phase space \({\mathbb{R}^{2d} \times \mathbb{S}^{2}}\) up to errors of second order in the semiclassical parameter. This is done via an Egorov-type theorem for normal Wigner–Weyl calculus for \({\mathbb{R}^d}\) (Folland, Harmonic Analysis on Phase Space, 1989; Lein, Weyl Quantization and Semiclassics, 2010) combined with the Stratonovich–Weyl calculus for SU(2) (Varilly and Gracia-Bondia, Ann Phys 190:107–148, 1989). For a specific class of Hamiltonians, including the Rabi- and Jaynes–Cummings model, we prove an Egorov theorem for times much longer than the semiclassical time scale. We illustrate the approach for a simple model of the Stern–Gerlach experiment. 相似文献
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It is reported about quantum chemical DFT calculations of various transition metal (TM) nitrido complexes which contain a TM‐N‐E linkage. The goal is to elucidate the nature of the TM‐N‐E bonding situation with modern quantum chemical tools. Five comparative investigations have been carried out. (a) Comparison of the N‐donor ability in the nitrido complexes Cl3W‐N‐ECln where ECln = NaCl, MgCl2, AlCl3. (b) Comparative analysis of the bonding situation in Cl4W‐N‐X where X = Na, MgCl, AlCl2, SiCl3, PCl2, SCl, Cl. (c) Comparison of the structure and bonding in Cl5W‐NPH3, Cl5W‐OPH3+, Cl4W‐(NPH3)(OPH3)+. (d) Comparative analysis of the bonding situation in Cl5Ta‐OPH3, Cl5W‐NPH3, Cl5Re‐CPH3. (e) Energy decomposition analysis of the bonding of the isolobal ligands NPH3 and Cp with WCl5. 相似文献
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Accurate density functional theory description of binding constants and NMR chemical shifts of weakly interacting complexes of C60 with corannulene‐based molecular bowls 下载免费PDF全文
Density functional calculations on “catch and release” complexes of C60 with corannulene derived molecular bowls show that computationally obtained 1H nuclear magnetic resonance (NMR) chemical shifts can be used as a reliable predictor of binding constants. A wide range of functionals was benchmarked against accurate ab initio calculations to ensure a credible representation of the weak forces that dominate the interactions in these systems. The most reliable density functional theory (DFT) results were then calibrated using experimentally observed NMR data. Careful analysis and comparison of a wide range of commonly used density functionals shows that the explicit inclusion of dispersion corrections is currently the only reliable way to accurately describe the systems investigated in our study. Moreover, we are able to show that the B97‐D and ωB97X‐D functionals are not only able to reproduce ab initio benchmark calculations, but they do so accurately with a moderately sized basis sets and without the problems of numerical integration we encountered with other functionals in this study. © 2013 Wiley Periodicals, Inc. 相似文献
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