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91.
Jin‐Yun Wang Chen‐Sheng Lin Min‐Yi Zhang Guo‐Liang Chai Wen‐Dan Cheng 《International journal of quantum chemistry》2012,112(4):1198-1208
Geometrical structures of three investigated molecules Sc3N@C80, Sc3N@C80‐Fc, and C60‐Fc were optimized by density functional theory (DFT) at the B3LYP/6‐31G* level. Then the time‐dependent DFT was employed to investigate the excited states of these molecules. After exohedral functionalization by ferrocene (Fc‐) group as the electron donor or replacing C60 with Sc3N@C80 as the electron acceptor, the wavelengths of the first one‐photon absorption peak and the strongest two‐photon absorption (2PA) and three‐photon absorption (3PA) peaks shift red. The corresponding cross sections of Sc3N@C80‐Fc in the 2PA and 3PA processes increase as compared with those of Sc3N@C80, which originate from the contributions of charge transfers from Fc‐ group to C80 cage and simultaneously the transfers from the C80 cage to the encapsulated Sc3N cluster. When compared with C60‐Fc, the 2PA and 3PA cross sections of Sc3N@C80‐Fc decrease, which may result from the more negative charge surface of C80 cage in Sc3N@C80‐Fc molecule which blocks the charge transfers from Fc‐ moiety to the C80 cage in the excitation processes by compared with C60‐Fc. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012 相似文献
92.
Garth J Simpson 《Chemphyschem》2004,5(9):1301-1310
Recent observations of remarkably large chiroptical effects in second-harmonic generation (SHG) and sum-frequency generation (SFG) measurements suggest exciting possibilities for the development of new chiral-specific spectroscopies and novel chiral materials for nonlinear optics. Several fundamental studies designed to elucidate the molecular and macromolecular origins of the chiral responses are reviewed to provide a framework for development of this emerging field. In general, the chiral activity in SHG and SFG has the potential to arise from complex interactions between hosts of different competing effects. Fortunately, relatively simple electric dipole-allowed mechanisms routinely dominate the nonlinear optical chiral activities of most practical systemsexpressions can often be generated to link the. This substantial reduction in complexity allows for the development of simple models connecting the macroscopic nonlinear optical response to intuitive molecular and supramolecular properties. 相似文献
93.
A comparative study for the fitting of X‐ray photoelectron spectra (XPS) using different model functions is presented. Synthetically generated test spectra using Gaussian/Lorentzian convolution and a real measured spectrum are fitted with the three commonly used models: product, sum and Gaussian/Lorentzian convolution functions. In these limited tests, it was found that the sum function is superior to the product function, particularly for low‐noise spectra. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
94.
For approximate wave functions, we prove the theorem that there is a one‐to‐one correspondence between the constraints of normalization and of the Fermi–Coulomb and Coulomb hole charge sum rules at each electron position. This correspondence is surprising in light of the fact that normalization depends on the probability of finding an electron at some position. In contrast, the Fermi–Coulomb hole sum rule depends on the probability of two electrons staying apart because of correlations due to the Pauli exclusion principle and Coulomb repulsion, while the Coulomb hole sum rule depends on Coulomb repulsion. We demonstrate the theorem for the ground state of the He atom by the use of two different approximate wave functions that are functionals rather than functions. The first of these wave function functionals is constructed to satisfy the constraint of normalization, and the second that of the Coulomb hole sum rule for each electron position. Each is then shown to satisfy the other corresponding sum rule. The significance of the theorem for the construction of approximate “exchange‐correlation” and “correlation” energy functionals of density functional theory is also discussed. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 相似文献
95.
Unique Vibrational Features as a Direct Probe of Specific Antigen–Antibody Recognition at the Surface of a Solid‐Supported Hybrid Lipid Bilayer 下载免费PDF全文
Here, we demonstrate how sum frequency generation (SFG), a vibrational spectroscopy based on a nonlinear three‐photon mixing process, may provide a direct and unique fingerprint of bio‐recognition; This latter can be detected with an intrinsically discriminating unspecific adsorption, thanks to the high sensitivity of the second‐order nonlinear optical (NLO) response to preferential molecular orientation and symmetry properties. As a proof of concept, we have detected the biological event at the solid/liquid interface of a model bio‐active antigen platform, based on a solid‐supported hybrid lipid bilayer (ss‐HLB) of a 2,4‐dinitrophenyl (DNP) lipid, towards a monoclonal mouse anti‐DNP complementary antibody. 相似文献
96.
Ratnadip De Prof. Dr. Benjamin Dietzek-Ivanšić 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(55):e202200407
Electrochemical interfaces are key structures in energy storage and catalysis. Hence, a molecular understanding of the active sites at these interfaces, their solvation, the structure of adsorbates, and the formation of solid-electrolyte interfaces are crucial for an in-depth mechanistic understanding of their function. Vibrational sum-frequency generation (VSFG) spectroscopy has emerged as an operando spectroscopic technique to monitor complex electrochemical interfaces due to its intrinsic interface sensitivity and chemical specificity. Thus, this review discusses the happy get-together between VSFG spectroscopy and electrochemical interfaces. Methodological approaches for answering core issues associated with the behavior of adsorbates on electrodes, the structure of solvent adlayers, the transient formation of reaction intermediates, and the emergence of solid electrolyte interphase in battery research are assessed to provide a critical inventory of highly promising avenues to bring optical spectroscopy to use in modern material research in energy conversion and storage. 相似文献
97.
考虑立体活性孤对电子附近次级键配位原子的贡献, 对文献报道的三十个氨基多羧酸锑(III)螯合物的晶体结构中配位多面体描述进行了全面的修正. 配位多面体的几何构型指定采用了单位球内截多面体的两面角判据及其相关的ANVPDA程序. 所有配位多面体几何构型的修正均得到了键价计算的有力支持. 相似文献
98.
《Acta Crystallographica. Section C, Structural Chemistry》2017,73(11):896-904
Since the discovery of electrochemically active LiFePO4, materials with tunnel and layered structures built up of transition metals and polyanions have become the subject of much research. A new quaternary arsenate, sodium calcium trinickel aluminium triarsenate, NaCa1–x Ni3–2x Al2x (AsO4)3 (x = 0.23), was synthesized using the flux method in air at 1023 K and its crystal structure was determined from single‐crystal X‐ray diffraction (XRD) data. This material was also characterized by qualitative energy‐dispersive X‐ray spectroscopy (EDS) analysis and IR spectroscopy. The crystal structure belongs to the α‐CrPO4 type with the space group Imma . The structure is described as a three‐dimensional framework built up of corner‐edge‐sharing NiO6, (Ni,Al)O6 and AsO4 polyhedra, with channels running along the [100] and [010] directions, in which the sodium and calcium cations are located. The proposed structural model has been validated by bond‐valence‐sum (BVS) and charge‐distribution (CHARDI) tools. The sodium ionic conduction pathways in the anionic framework were investigated by means of the bond‐valence site energy (BVSE) model, which predicted that the studied material will probably be a very poor Na+ ion conductor (bond‐valence activation energy ∼7 eV). 相似文献
99.
Most of TM6-cluster compounds (TM = transition metal) are soluble in polar solvents, in which the cluster units commonly remain intact, preserving the same atomic arrangement as in solids. Consequently, the redox potential is often used to characterize structural and electronic features of respective solids. Although a high lability and variety of ligands allow for tuning of redox potential and of the related spectroscopic properties in wide ranges, the mechanism of this tuning is still unclear. Crystal chemistry approach was applied for the first time to clarify this mechanism. It was shown that there are two factors affecting redox potential of a given metal couple: Lever’s electrochemical parameters of the ligands and the effective ionic charge of TM, which in cluster compounds differs effectively from the formal value due to the bond strains around TM atoms. Calculations of the effective ionic charge of TMs were performed in the framework of bond valence model, which relates the valence of a bond to its length by simple Pauling relationship. It was also shown that due to the bond strains the charge depends mainly on the atomic size of the inner ligands. 相似文献
100.
In this talk, we give a short review of our recent works on studying the singly heavy baryon, doubly heavy baryon, and triply heavy baryon spectra from QCD sum rules. 相似文献