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41.
Aromaticity and Chemical Bonding of Chalcogen-Bonded Capsules Featuring Enhanced Magnetic Anisotropy
Prof. Demeter Tzeli Dr. Ioannis D. Petsalakis Dr. Giannoula Theodorakopoulos Dr. Faiz-Ur Rahman Prof. Pablo Ballester Prof. Julius Rebek Jr. Prof. Yang Yu 《Chemphyschem》2020,21(19):2187-2195
We present a theoretical study of chalcogen bonded container capsules ( AX+AX ) where X=O, S, Se, and Te, and their encapsulation complexes with n-C9H20 (n-C9H20@ AX+AX ). Both Se and Te encapsulation complexes have significant experimental and computed binding energies, analogous to the hydrogen bonded counterparts, while the S and O capsules and their encapsulation complexes show only weak binding energies, which are attributed to different types of bonding: chalcogen S⋅⋅⋅N bonds for S-capsules and π–π stacking and weak hydrogen bonds for the O case. All AX+AX and C9H20@ AX+AX present unusually high magnetic anisotropies in their interiors. The 1H NMR spectra of the encapsulation complexes display the proton signals of the encapsulated n-nonane highly upfield shifted, in agreement with the available experimental data for the Se capsule. We found that different factors contribute to the observed magnetic anisotropy of the capsule's interior: for the Te capsule the most important factor is Te's large polarizability; for the O analogue the inductive effects produced by the electronegative nature of the O and N heteroatoms; and for the S and Se capsules, the polarizability of the heteroatoms combines with electric field effects. 相似文献
42.
M. Türky?lmazoglu J.S.B. GajjarRID=""ID="" All correspondence should be addressed to Dr. J.S.B. Gajjar. A.I. Ruban 《Theoretical and Computational Fluid Dynamics》1999,13(2):91-114
RID="ID=" Communicated by P. HallAbstract:The absolute/convective instability of two-dimensional wakes forming behind a flat plate and near the trailing-edge of a thin
wedge-shaped aerofoil in an incompressible/compressible fluid is investigated. The mean velocity profiles are obtained by
solving numerically the classical compressible boundary-layer equations with a negative pressure gradient for the flat plate
case, and the incompressible triple-deck equations for a thin wedge-shaped trailing-edge. In addition for a Joukowski aerofoil
the incompressible mean boundary-layer flow in the vicinity of the trailing-edge is also calculated by solving the interactive
boundary-layer equations. A linear stability analysis of the boundary-layer profiles shows that a pocket of absolute instability
occurs downstream of the trailing-edge with the extent of the instability region increasing with more adverse pressure gradients.
The region of absolute instability persists along the near-wake axis, while the majority of the wake is convectively unstable.
For a thin wedge-shaped trailing-edge in an incompressible fluid, a similar stability analysis of the velocity profiles obtained
via a composite expansion, also shows the occurrence of absolute instability behind the trailing-edge for a wedge angle greater
than a critical value. For increasing values of the wedge angle and for thicker aerofoils, separation takes place near the
trailing-edge and the extent of absolute instability increases. Calculations also show that for insulated plates compressibility
has a stabilizing effect but cooling the wall destabilizes the flow unlike wall heating.}
Received 11 May 1998 and accepted 25 February 1999 相似文献
43.
Ioannis D. Petsalakis Giannoula Theodorakopoulos Anna Grochol Pawel Kowalczyk Wodzimierz Jastrzebski 《Chemical physics》2009,362(3):130-134
Theoretical multireference configuration interaction (MRDCI) calculations on the excited 1Σ+ and 1Π states of NaLi are presented. They improve the results of a previous study by two of the present authors, resolve some differences with other theoretical results and lead to overall good agreement with experimental observations. To extend the experimental data base of electronic states in NaLi, a previously unknown 1Σ+ state is investigated by polarisation labelling spectroscopy. Comparison with accompanying and previous theoretical calculations leads to a conclusion that the observed system consists of two band systems switching smoothly from one adiabatic state to the other and allows assignment of the bands as 51Σ+ ← X1Σ+ in the lower energy part and to 61Σ+ ← X1Σ+ for higher energies. 相似文献
44.
Ashraf Ghanem Volker SchurigRID="a"ID="a" Dedicated to the Memory of Prof. <E>E. Bayer</E> – 《Monatshefte für Chemie / Chemical Monthly》2003,134(8):1151-1157
Summary. Asymmetric acetylation of a set of secondary alcohols with the innocuous acyl donor isopropenyl acetate catalyzed by a lipase from Pseudomonas cepacia immobilized on ceramic particles (PSL-C) in toluene as organic medium afforded the chiral alcohols and the corresponding acetates in high enantiomeric excess (up to 99%). An effective baseline separation of the enantiomers of both substrate and product was performed in one analysis without derivatization using gas chromatography on a new chiral stationary phase (CSP) Chirasil--Dex containing an undecamethylene spacer (C11-Chirasil-Dex).Received November 27, 2002; accepted (revised) January 9, 2003
Published online June 2, 2003 相似文献
45.
Giannoula Theodorakopoulos Ioannis D Petsalakis Mark S Child 《Journal of Molecular Structure》1998,434(1-3)
A three-dimensional potential energy function has been calculated for the X1Σ+g state of NO+2 from ab initio MRD-CI data. With this PE function, converged vibrational calculations have also been performed for ten vibrational states, with the aid of a computer program developed in the present work for this purpose. The calculated harmonic frequencies, vibrational term values and rotational constants are in good agreement with experimental data. 相似文献
46.
Giannoula Theodorakopoulos Ioannis D. Petsalakis Cleanthes A. Nicolaides Robert J. Buenker 《Chemical physics》1985,100(3)
Oscillator strengths for transitions between the
1A1 ground state of water and its
1A1 and
1A1 excited states are computed employing two different theoretical approaches. In one series of calculations a common orthonormal one-electron basis is employed for all of the above states, while in the other type of treatment two different, mutually non-orthogonal, sets are used; the multireference single- and double-excitation (MRD CI) method is employed in each case, with configuration selection, to generate the various electronic wavefunctions. It is found that the use of ground-state SCF MOs leads to poor convergence in the wavefunctions of the (Rydberg-type)
1A1 and
1A1 excited states and consequently also for the corresponding
---
and
---
f-values; this behavior is seen to be closely related to the near degeneracy of the two excited states, each of which is a mixture of the 3a1 → 3sa1 and 1b1 → 3pb1 configurations. Analogous computations with the
1B11b1 → 3sa1 MOs show much better convergence properties, and the resulting f-values compare well with what is obtained when state-specific orbital sets are employed separately for ground and excited states and non-orthonormal techniques are applied to compute the desired transition moments. These results tend to confirm previous findings which indicate conceptual and computational advantages for the calculation of excited-state wavefunctions and properties within the context of a state-specific theory. They also show that although the goal of eliminating the dependence of MRD CI calculations on the choice of MO basis is very nearly approached for energy quantities, it is less satisfactorily achieved for other properties, especially when the existence of nearly degenerate electronic states is a critical factor. 相似文献
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49.
Alexander KomechRID=""ID=""Supported partly by French–Russian A.M.Liapunov Center of Moscow State University by Max-Planck Institute for Mathematics in the Sciences by research grants of INTAS of Volkswagen-Stiftung. Markus KunzeRID=""ID=""Supported by DAAD andNSF during a stay at Brown University
<AU><FNMS>Herbert<SNM>Spohn<ORF RID="a" 《Communications in Mathematical Physics》1999,203(1):1-19
50.
Pierre?SchapiraEmail authorView authors OrcID profile 《Mathematical Physics, Analysis and Geometry》2017,20(3):21
We extend the classical Wick rotation to D-modules and higher codimensional submanifolds. 相似文献