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1.
Geometries and stabilization energies of various simple H-bonded complexes (water dimer, hydrogen fluoride dimer, formamide
dimer, formic acid dimer) have been determined by a gradient optimization that eliminates the basis set superposition error
(BSSE) by the counterpoise (CP) method in each gradient cycle as well as by the standard gradient optimization. Both optimization
methods lead to different potential energy surfaces (PES). The difference depends on the theoretical level used and is larger
if correlation energy is considered. Intermolecular distances from the CP-corrected PES are consistently longer, and this
difference might be significant (∼0.1 ?); also angular characteristics determined from both surfaces differ significantly.
Different geometries were obtained even when passing to larger basis sets (aug-cc-pVDZ). The standard optimization procedure
can result in a completely wrong structure. For example, the “quasi-linear” structure of the (HF)2 (global minimum) does not exist at the standard MP2/ 6-31G** PES (where only cyclic structure was detected) and is found
only at the CP-corrected PES. Stabilization energies obtained from the CP-corrected PES are always larger than these from
the standard PES where the BSSE is added only a posteriori for the final optimized structure; both energies converge only
when passing to a larger basis set (aug-cc-pVDZ).
Received: 11 March 1998 / Accepted: 19 June 1998 / Published online: 4 September 1998
RID="
ID=" <E6>Acknowledgements.</E6> The project was supported by the Grant Agency of the Czech Republic (Grant No. 203/98/1166).
RID="
ID=" <E5>Correspondence to</E5>: P. Hobza 相似文献
2.
3.
依据系统工程理论的原理和方法,研究了Sr、B、Zn、Mo、Cu五种微显元素对中甘11号结球甘蓝产量、品质的影响及各因子间的复合效应。试验结果表明,各因子对中甘11号产量的作用是:Sr>B>Zn>Cu>Mo。获得了中甘11号亩产在6000kg以上的优化组合方案是:Sr0.054%~0.061%,B0.035%~0.042%,Zn0.047%~0.057%,Mo0.032%~0.038%,Cu0.050%~0.056%,为微量元素在蔬菜上的应用提供了科学依据. 相似文献
4.
The color of a complex number is defined as the number of vertices of the convex hull of powers of that number. This induces a coloring of the unit disk. The structure of the set of points where the color changes is investigated here. It is observed that there is a connection between this fractal set and some family of trinomial equations. Three algorithms for coloring the unit disk are described, the last one (related to the Farey sequence) arising out of a conjecture. This conjecture is formulated and proved in this presentation. 相似文献
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6.
《Communications in Nonlinear Science & Numerical Simulation》2014,19(6):2005-2011
A new 4-D fractional-order chaotic system without equilibrium point is proposed in this paper. There is no chaotic behavior for its corresponding integer-order system. By computer simulations, we find complex dynamical behaviors in this system, and obtain that the lowest order for exhibiting a chaotic attractor is 3.2. We also design an electronic circuit to realize this 4-D fractional-order chaotic system and present some experiment results. 相似文献
7.
Despite the apparent simplicity of the copper(I) iodide catalyzed CuAAC reaction, the conversion of the catalytic species, i.e. Cu(I) to thermodynamically more stable Cu(II), via aerial oxidation or disproportionation is a major issue. To stabilize the Cu(I) species, the reaction is ideally carried out under an inert atmosphere in the presence of additives such as alcohols, amines, thiols, and aldehydes. Herein, we report the first CuI catalyzed click reaction without an inert atmosphere by employing the CuI/l-proline system in glycerol. The method showed remarkable stability towards sensitive functional groups such as acetonides and 1,2,4-trioxanes. 相似文献
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9.
Yuru Zou Yuanyuan Yao Wenxia Li 《Journal of Mathematical Analysis and Applications》2008,340(2):1422-1432
Based on a scheme by Lau and Ngai, a sufficient and necessary condition for an IFS of contractive similitudes to satisfy the open set condition is given. A class of Sierpinski carpets with parameters (λ1,λ2) is then investigated. 相似文献