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71.
72.
We present a comparative study on the C-H stretching vibrations at air/DMSO (dimethyl sulfoxide) interface with both the free-induction decay (FID) coherent vibrational dynamics and the sub-wavenumber high resolution sum-frequency generation vibrational spectroscopy measurements. In principle the frequency-domain and time-domain spectroscopic measurements should generate identical information for a given molecular system. However, when the molecular systems are with several coupled or overlapping vibrational modes, obtain- ing detailed spectroscopic and coherent dynamics information is not as straightforward and rather difficult from either the time-domain or the frequency domain measurements. For the case of air/DMSO interface that is with moderately complex vibrational spectra, we show that the frequency-domain measurement with sub-wavenumber high-resolution sum-frequency generation vibrational spectroscopy is probably more advantageous than the time- domain measurement in obtaining quantitative understanding of the structure and coherent dynamics of the molecular interface. 相似文献
73.
Yutong Zhao Fu Kit Sheong Jian Sun Pedro Sander Xuhui Huang 《Journal of computational chemistry》2013,34(2):95-104
We implemented a GPU‐powered parallel k‐centers algorithm to perform clustering on the conformations of molecular dynamics (MD) simulations. The algorithm is up to two orders of magnitude faster than the CPU implementation. We tested our algorithm on four protein MD simulation datasets ranging from the small Alanine Dipeptide to a 370‐residue Maltose Binding Protein (MBP). It is capable of grouping 250,000 conformations of the MBP into 4000 clusters within 40 seconds. To achieve this, we effectively parallelized the code on the GPU and utilize the triangle inequality of metric spaces. Furthermore, the algorithm's running time is linear with respect to the number of cluster centers. In addition, we found the triangle inequality to be less effective in higher dimensions and provide a mathematical rationale. Finally, using Alanine Dipeptide as an example, we show a strong correlation between cluster populations resulting from the k‐centers algorithm and the underlying density. © 2012 Wiley Periodicals, Inc. 相似文献
74.
The perfluoroalkyl substances(PFS) have attracted considerable attention in recent years as a persistent global pollutant to be able to bioaccumulate in higher organisms.In this paper,theoretical analysis on electronic structures,optoelectronic properties and absorption spectra properties of the perflurooctane sulfonate(PFOS) in gas phase have been investigated by using the DFT/TD-DFT method.The geometric structures,electrostatic potentials,energy gaps,ionization potentials,electron affinities,frontier molecular orbital,excitation energies and absorption spectra for the ground state of PFOS were calculated.The result indicates that the ability of accepting electron of neutral PFOS is larger than that of anionic PFOS,while the electron excited by UV irradiation from HOMO to LUMO in the anionic PFOS is easier than that in the neutral PFOS. 相似文献
75.
LUO Ya-Nan XU Xian-Zhua YU Xiao-Yang ZHU Guang-Shan QU Xiao-Shu ZHANG Xiao YU Li-Ying 《结构化学》2013,(11):1667-1672
A new coordination polymer, {[CdL(en)]'DMF}n (1, H2L = 4-[(8-hydroxy-5- quinolinyl)azo]-benzenesulfonic acid, en = ethylenediamine, DMF = N,N-dimethylformamide), has been solvothermally synthesized and structurally characterized by single-crystal X-ray diffrac- tion, infrared (IR) spectra, elemental analysis, powder X-ray diffractions (PXRD) and thermo- gravimetric analysis (TGA). Compound 1 crystallizes in monoclinic, space group P2Jc with a = 14.6525(9), b = 13.3917(9), c = 11.8838(8) A, β = 101.2290(10)°, V = 2287.2(3) A3, Z = 4, C20H24CdN6OsS, Mr = 572.91, Dc. = 1.664 mg-mm-3, F(000) = 1160, p = 1.091 mm-1, R = 0.0232 and wR = 0.0587 for 3597 observed reflections (I 〉 2σ(I)). Compound 1 exhibits a one-dimensional (1D) double-chain structure which is further connected through hydrogen bonding and π-π interactions into a three-dimensional (3D) supramolecular network. In addition, it exhibits blue fluorescence at room temperature in the solid state. 相似文献
76.
A new coordination polymer, [Ag(3,3-pybz)(3,3-Hpybz)]n (1, 3,3-Hpybz = 3-pyri- din-3-yl-benzoic acid), has been synthesized and characterized by elemental analysis, IR spectra, PXRD, and single-crystal X-ray diffraction. In complex 1, the Ag(1)ions are linked by the paired 3,3-pybz ligands to generate an infinite 1D loop chain, and further through π-π stacking interactions to form a 2D supramolecular architecture. Crystal data for 1: triclinic, space group P1, a = 10.2635(17), b = 10.3041(12), c = 10.8060(13) A, V= 1679.1(5)A3, α = 62.028(11), β = 80.325(15), γ = 78.738(14)°, Z = 2, C24H17AgN2O4, Mr = 505.27, Dc= 1.698 g/cm3, μ= 1.058 mm--, F(000) = 506, S = 1.012 and T = 293(2) K. The final R = 0.0293 and wR = 0.0667 for 3435 observed reflections with I〉 2a(/), and R = 0.0350 and wR = 0.0688 for all data. 相似文献
77.
A new 1D chain copper coordination polymer [CuE(H2L)2(C10HsN2)(HEO)2]n'3n(H20) with 2,3-pyridinedi carboxylic acid (H2L) and 2,2'-bipyridine (2,2'-bipy) as ligands has been synthesized in the mixed ethanol and water solvents. Crystal data for this complex are as follows: monoclinic, space group P2Jc, a = 7.7713(7), b = 27.478(3), c = 13.2621(13)/1,, fl = 100.6940(10), V= 2782.8(5) A3, Dc = 1.722 g/cm3, Z = 4, p = 1.61 mm-1, F(000) = 1472, the final R = 0.0363 and wR = 0.0933. In the crystal structure, the whole molecule consists of two cooper ions, two H2L, one 2,2"-bipy molecule and six water molecules. Each central copper ion is coordinated with three oxygen atoms from two H2L and one water molecule, two nitrogen atoms from one 2,2'-bipy molecule and two H2L, giving a distorted tetragonal pyramidal geometry. Thermal stability properties of the complex were investigated. 相似文献
78.
Syntheses,Structures, Luminescent Properties and Photocatalytic Activities of Two Lead(II) Compounds
CONG Yao MA Cai-Lian CHE Guang-Bo BAI Hong-Ye SUN He-Yi REN Ao LIU Chun-Bo 《结构化学》2013,(11):1673-1679
Two lead(ll) compounds, [Pb(qlc)(phen)2(NO3)]e-H20 (1) and [Pb(qlc)z(phen)]-3H20 (2) (Hqlc = quinoline-3-carboxylic acid, phen = 1,10-phenanthroline), were synthesized and charac- terized by elemental analysis, single-crystal X-ray diffraction, IR and thermogravimetric analysis. Crystal 1 is of monoclinic, space group C2/c with a = 25.246(5), b = 12.543(3), c = 18.917(4) A, β = 105.77(3)°, V= 5765(2) A3, Z = 4, C68H46N12OllPb2, Mr = 1621.53, Dc = 1.886 g.cm-3,/.t(MoKa) = 5.912 mm-1, F(000) = 3152, GOOF = 1.080, the final R = 0.022 and wR = 0.0571 for 4822 observed reflections (1 〉 2a(/)). Crystal 2 is oftriclinic, space group Pi with a = 8.7883(10), b = 11.7031 (13), c = 15.9320(17) A, a = 69.9400(10), fl = 78.9780(10), 7 = 79.1650(10)°, V = 1497.4(3) A3, Z = 2, C32H26NaO7Pb, Mr. = 785.71, Dc = 1.729 g.cm-s, p(MoKa) = 5.688 mm-1, F(000) = 756, GOOF = 1.106, the final R = 0.0313 and wR = 0.088 for 59i5 observed reflections (1 〉 2σ(I)). Single-crystal X-ray diffraction analysis reveals that 1 exhibits a two-dimensional (2D) layer based on π-π stacking interactions between phen. Simultaneously, the adjacent 2D layers are assembled via π-π stacking interactions between phen and quinoline tings into a 3D supramolecular structure. The zero- dimensional structure of 2 is also further extended by π-π interactions to form a 2D supramolecular layer. Furthermore, these two compounds exhibit photoluminescence at room temperature in the solid state and their photocatalytic activities have been studied by degradation methylene blue. 相似文献
79.
Hyeonbae Kang Hyundae Lee Mikyoung Lim 《Mathematical Methods in the Applied Sciences》2015,38(9):1847-1854
We present a new systematic method to compute the Riemann mapping from the outside of the unit disc to the outside of a simply connected domain. We derive explicit relations between the coefficients of the Riemann mapping and the generalized polarization tensors associated with the domain. Because the generalized polarization tensors can be computed numerically, we are able to compute the coefficients of the Riemann mapping using these relations. Effectiveness of the method is validated by numerical examples. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
80.
Shinya Miyajima 《Numerical Linear Algebra with Applications》2015,22(3):548-563
Fast algorithms for enclosing the minimum norm least squares solution of the matrix equation AXB = C are proposed. To develop these algorithms, theories for obtaining error bounds of numerical solutions are established. The error bounds obtained by these algorithms are verified in the sense that all the possible rounding errors have been taken into account. Techniques for accelerating the enclosure and obtaining smaller error bounds are introduced. Numerical results show the properties of the proposed algorithms. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献