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Results 201 - 250 of 1666
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Wood Brandon C - - 2012
We perform density-functional theory calculations on model surfaces to investigate the interplay between the morphology, electronic structure, and chemistry of oxygen- and hydroxyl-rich surfaces of InP(001) and GaP(001). Four dominant local oxygen topologies are identified based on the coordination environment: M-O-M and M-O-P bridges for the oxygen-decorated surface; and M-[OH]-M ...
Niu Kai - - 2012
The third-order polarization for coherent anti-Stokes Raman scattering (CARS) from a pure state is described by 48 terms in perturbation theory, but only 4 terms satisfy the rotating wave approximation. They are represented by Feynman dual time-line diagrams and four-wave mixing energy level diagrams. In time-resolved (tr) fs and fs/ps ...
Bruni F - - 2012
By combining neutron diffraction and Monte Carlo simulations, we have determined the microscopic structure of the hydration ions shell in aqueous solutions of MgCl(2) and CaCl(2), along with the radial distribution functions of the solvent. In particular the hydration shell of the cations, show cation specific symmetry, due to the ...
Tan Hong Kee - - 2012
It has been demonstrated in our studies that the intrinsic curvature of DNA can be easily interrupted by low concentrations of chloroquine and ethidium bromide. In addition, the changes of DNA curvature caused by varying the concentration of these two DNA intercalators can be readily verified through using an atomic ...
Jaeger Heather M - - 2012
Multi-exciton generation (MEG), the creation of more than one electron-hole pair per photon absorbed, occurs for excitation energies greater than twice the bandgap (E(g)). Imperfections on the surface of quantum dots, in the form of atomic vacancies or incomplete surface passivation, lead to less than ideal efficiencies for MEG in ...
Hartkamp Remco - - 2012
The transient-time correlation function (TTCF) method is used to calculate the nonlinear response of a homogeneous atomic fluid close to equilibrium. The TTCF response of the pressure tensor subjected to a time-independent planar mixed flow of shear and elongation is compared to directly averaged non-equilibrium molecular dynamics (NEMD) simulations. We ...
Shew Chwen-Yang - - 2012
Several single-modal Debye correlation functions to approximate part of the overall Debey correlation function of liquids are closely examined for elucidating their behavior in the corresponding spin echo small angle neutron scattering (SESANS) correlation functions. We find that the maximum length scale of a Debye correlation function is identical to ...
Mebs Stefan - - 2012
The experimental electron density of sumanene, C(21)H(12), was extracted from a high resolution X-ray data set measured at 100 K and topologically analyzed. In addition to bond topological and atomic properties, information about the density distribution between adjacent molecules, which show close CC approaches of ∼3.4 Å within the columnar ...
Knippenberg S - - 2012
An earlier proposed approach to molecular response functions based on the intermediate state representation (ISR) of polarization propagator and algebraic-diagrammatic construction (ADC) approximations is for the first time employed for calculations of nonlinear response properties. The two-photon absorption (TPA) spectra are considered. The hierarchy of the first- and second-order ADC∕ISR ...
Eilam Asaf - - 2012
We propose a method based on the electromagnetically induced transparency (EIT) phenomenon for the detection of molecules which exist as a small minority in the presence of a majority of absorbers. The EIT effect we employ effectively eliminates the absorption of the majority species in the spectral region where it ...
Alexander Andrew J - - 2012
A protocol has been developed for production of intense crystalloluminescence (XTL) from sodium chloride in aqueous solution by selective doping with transition metal salts (Ag(+), Cu(2+), and Dy(3+)). The method was used to record complete, fully dispersed deep UV-visible (200-650 nm) XTL spectra of sodium chloride for the first time. ...
Raghunathan Shampa - - 2012
Explicitly time-dependent density functional theory (TDDFT) is a formally exact theory, which can treat very large systems. However, in practice it is used almost exclusively in the adiabatic approximation and with standard ground state functionals. Therefore, if combined with coherent control theory, it is not clear which control tasks can ...
Miura Tsuyoshi - - 2012
A fluorous organocatalyst promotes direct asymmetric aldol reactions of aromatic aldehydes with ketones in brine to afford the corresponding anti-aldol products in high yield with up to 96% ee. Fluorous organocatalyst can be readily recovered by solid phase extraction using fluorous silica gel and reused without purification.
Terada Tadashi - - 2012
Schneiderian papilloma (SP) is classified into three types: inverted, oncocytic, and exophytic. Malignant transformation occurs in 10% of SP; most are inverted and oncocytic types. Malignant transformation of polypoid exophytic SP is exceptional; only two cases have been reported in the English literature. A 58-year-old man consulted our hospital because ...
Gaiduk Alex P - - 2012
The common way to obtain energies from Kohn-Sham exchange potentials is by using the Levy-Perdew virial relation. For potentials that are not functional derivatives (i.e., nearly all model exchange potentials in existence), this approach leads to energy expressions that lack translational and rotational invariance. We propose a method for constructing ...
Reva Igor - - 2012
Spontaneous and near-infrared∕infrared (NIR∕IR)-induced interconversions between two amino-hydroxy conformers of monomeric cytosine have been investigated for the compound isolated in a low-temperature argon matrix. Combined use of a laser source (which provides narrowband NIR radiation) and a broadband NIR/IR source of excitation light allowed a detailed investigation of mutual conversions ...
Tonge Nicola M - - 2012
We report the first spectroscopic study of a complex consisting of a rare earth atom in combination with ammonia. Using two-color resonance-enhanced multiphoton ionization (REMPI) spectroscopy, the lowest energy electronic transition of YbNH(3) has been found in the near-infrared. The spectrum arises from a spin-forbidden transition between the (1)A(1) ground ...
Shin Hyeondeok - - 2012
Path-integral Monte Carlo calculations have been performed to study (4)He adsorption on a single C(60) molecule. Helium corrugations on the fullerene molecular surface are incorporated with the (4)He-C(60) interaction described by the sum of all (4)He-C interatomic pair potentials. Radial density distributions show a layer-by-layer growth of (4)He with the ...
Silverstein Daniel W - - 2012
A vibronic coupling model based on time-dependent wavepacket approach is applied to simulate linear optical processes, such as one-photon absorbance and resonance Raman scattering, and nonlinear optical processes, such as two-photon absorbance and resonance hyper-Raman scattering, on a series of small molecules. Simulations employing both the long-range corrected approach in ...
Thilagam A - - 2012
The non-Hermitian quantum dynamics of excitonic energy transfer in photosynthetic systems is investigated using a dissipative two-level dimer model. The approach is based on Green's function formalism which permits consideration of decoherence and intersite transfer processes on comparable terms. The results indicate a combination of coherent and incoherent behavior at ...
Santosh Mogurampelly - - 2012
In an effort to design efficient platform for siRNA delivery, we combine all atom classical and quantum simulations to study the binding of small interfering RNA (siRNA) by pristine single wall carbon nanotube (SWCNT). Our results show that siRNA strongly binds to SWCNT surface via unzipping its base-pairs and the ...
Birzniece I - - 2012
The diode laser induced B(1)(1)Π → X(1)Σ(+) fluorescence spectra of the KCs molecule were recorded by Fourier-transform spectrometer with resolution of 0.03 cm(-1). Buffer gas Ar was used to facilitate appearance of rotation relaxation lines in the spectra, thus enlarging the B(1)(1)Π dataset, allowing one to determine the Λ-splitting constants ...
Cajahuaringa Samuel - - 2012
We use molecular simulation to analyze liquid dynamics in the vicinity of the liquid-liquid phase transition (LLPT) recently discovered in the modified embedded-atom model for elemental gallium. For this purpose we analyze the diffusive behavior in terms of the mean-squared displacement and self-intermediate scattering functions for two systems obtained by ...
Stephens Susanna L - - 2012
Pure rotational spectra of the ground vibrational states of six isotopologues of OC⋅⋅⋅AgI have been measured by chirped-pulse Fourier transform microwave spectroscopy. The spectra are assigned to determine the rotational constant, B(0), centrifugal distortion constant, D(J), and nuclear quadrupole coupling constant of the iodine atom, χ(aa)(I). The complex is linear. ...
Calandra Pietro - - 2012
This work focuses on the dynamic phenomena emerging in self-assembled transient intermolecular networks formed when two different surfactants are mixed. In particular, the relaxation processes in liquid mixtures composed by bis(2-ethylhexyl)amine (BEEA) and octanoic acid (OA) in the whole composition range has been investigated by dielectric spectroscopy and Brillouin spectroscopy. ...
Groot Robert D - - 2012
Long-range hydrodynamics between colloidal particles or fibers is modelled by the fluid particle model. Two methods are considered to impose the fluid boundary conditions at colloidal surfaces. In the first method radial and transverse friction forces between particle and solvent are applied such that the correct friction and torque follows ...
Kawata Isao - - 2012
A new method for analyzing and visualizing the molecular excited states, named "excited state paired interacting orbital (EPIO)," is proposed. The method is based both on the paired interacting orbital (PIO) proposed by Fujimoto and Fukui [J. Chem. Phys. 60, 572 (1974)] and the natural transition orbital (NTO) by Martin ...
Li Huashan - - 2012
Transition state analyses have been carried out within a density functional theory setting to explain and quantify the distinctly different ways in which hydrogen and methyl terminations serve to protect silicon surfaces from the earliest onset of oxidation. We find that oxidation occurs via direct dissociative adsorption, without any energy ...
Navin J K - - 2012
Effusive molecular beam measurements of angle-resolved thermal dissociative sticking coefficients for CH(4) impinging on a Pt(111) surface, at a temperature of 700 K, are reported and compared to theoretical predictions. The reactivity falls off steeply as the molecular angle of incidence increases away from the surface normal. Successful modeling of ...
Adams Christopher L - - 2012
We present low-energy velocity map photoelectron imaging results for bare and Ar-solvated 1-nitropropane and 1-nitrobutane anions. We report the adiabatic electron affinity of 1-nitropropane as (223 ± 6) meV and that of 1-nitrobutane as (240 ± 6 meV). The vertical detachment energies of these two species are found to be ...
Zhang Bo - - 2012
We have used density functional theory (DFT) employing several different exchange-correlation functionals (PW91, PBE, PBEsol, TPSS, and revTPSS) coupled with lattice dynamics calculations to compute the thermodynamics of CO(2) absorption∕desorption reactions for selected transition metal oxides, (TMO), and hydroxides, TM(OH)(2), where TM = Mn, Ni, Zn, and Cd. The van't ...
Silverstein Daniel W - - 2012
A comprehensive vibronic coupling model based on the time-dependent wavepacket approach is derived to simulate linear optical processes, such as one-photon absorbance and resonance Raman scattering, and nonlinear optical processes, such as two-photon absorbance and resonance hyper-Raman scattering. This approach is particularly well suited for combination with first-principles calculations. Expressions ...
Ryabov Artem - - 2012
We investigate a diffusive motion of a system of interacting Brownian particles in quasi-one-dimensional micropores. In particular, we consider a semi-infinite 1D geometry with a partially absorbing boundary and the hard-core inter-particle interaction. Due to the absorbing boundary the number of particles in the pore gradually decreases. We present the ...
Miao Meng - - 2012
Using first-principles calculations we have studied the reactions of water over Ti adatoms on the (110) surface of rutile TiO(2). Our results provide fundamental insights into the microscopic mechanisms that drive this reaction at the atomic level and assess the possibility of using this system to activate the water dissociation ...
Dudowicz Jacek - - 2012
The lattice cluster theory (LCT) for the thermodynamics of a wide array of polymer systems has been developed by using an analogy to Mayer's virial expansions for non-ideal gases. However, the high-temperature expansion inherent to the LCT has heretofore precluded its application to systems exhibiting strong, specific "sticky" interactions. The ...
Sabass Benedikt - - 2012
Active diffusiophoresis-swimming through interaction with a self-generated, neutral, solute gradient-is a paradigm for autonomous motion at the micrometer scale. We study this propulsion mechanism within a linear response theory. First, we consider several aspects relating to the dynamics of the swimming particle. We extend established analytical formulae to describe small ...
Philpott Michael R - - 2012
The three step auf bau of a triangular polyaromatic protrusion attached to a larger parent hexagonal shaped graphene nanodot (GND) is described and the dichotomy between intrinsic protrusion localized magnetism and parent extended zigzag edge magnetism is explored using ab initio density functional theory calculations of spin and charge distributions ...
Huang Jing - - 2012
We investigate the spin transport properties of iron-phthalocyanine (FePc) molecule sandwiched between two N-doped graphene nanoribbons (GNRs) based on the density functional theory and nonequilibrium Green's function methods. Our calculated results clearly reveal that the FePc molecular junction has high spin-filter efficiency as well as negative differential resistance (NDR). The ...
Huntington Lee M J - - 2012
We have recently introduced a parameterized coupled-cluster singles and doubles model (pCCSD(α, β)) that consists of a bivariate parameterization of the CCSD equations and is inspired by the coupled electron pair approximations. In our previous work, it was demonstrated that the pCCSD(-1, 1) method is an improvement over CCSD for ...
Shao Zhuo - - 2012
The energy levels of CH(3)Cl(+)X̃(2)E showing strong spin-vibronic coupling effect (Jahn-Teller effect) have been measured up to 3500 cm(-1) above the ground vibrational state using one-photon zero-kinetic energy photoelectron and mass-analyzed threshold ionization spectroscopic method. Theoretical calculations have been also performed to calculate the spin-vibronic energy levels using a diabatic ...
Huggins David J - - 2012
Water is one of the simplest molecules in existence, but also one of the most important in biological and engineered systems. However, understanding the structure and dynamics of liquid water remains a major scientific challenge. Molecular dynamics simulations of liquid water were performed using the water models TIP3P-Ewald, TIP4P-2005, TIP5P-Ewald, ...
Kuo Ying-Ju - - 2012
Prostate cancer has seen a rapid rise in Taiwanese men. The current study was undertaken to evaluate trends of the disease diagnosed on prostate needle biopsy during a ten-year period at the Department of Pathology, Taipei Veterans General Hospital. The study included 8236 men who underwent a total of 9995 ...
Vilar Jose M G - - 2012
Many important processes at the microscale require far-from-equilibrium conditions to occur, as in the functioning of mesoscopic bioreactors, nanoscopic rotors, and nanoscale mass conveyors. Achieving such conditions, however, is typically based on energy inputs that strongly affect the thermal properties of the environment and the controllability of the system itself. ...
Swiatla-Wojcik Dorota - - 2012
Flexible models of the radical and water molecules including short-range interaction of hydrogen atoms have been employed in molecular dynamic simulation to understand mechanism of (●)OH hydration in aqueous systems of technological importance. A key role of H-bond connectivity patterns of water molecules has been identified. The behavior of (●)OH(aq) ...
Andreussi Oliviero - - 2012
The solvation model proposed by Fattebert and Gygi [J. Comput. Chem. 23, 662 (2002)] and Scherlis et al. [J. Chem. Phys. 124, 074103 (2006)] is reformulated, overcoming some of the numerical limitations encountered and extending its range of applicability. We first recast the problem in terms of induced polarization charges ...
Iuchi Satoru - - 2012
A simple model electronic Hamiltonian to describe the potential energy surfaces of several low-lying d-d states of the [Fe(bpy)(3)](2+) complex is developed for use in molecular dynamics (MD) simulation studies. On the basis of a method proposed previously for first-row transition metal ions in aqueous solution, the model Hamiltonian is ...
Frenette Catherine - - 2012
Hepatocellular carcinoma (HCC) is a lethal disease in most patients, due to its aggressive course and a lack of effective systemic therapies for advanced disease. Surgical resection and liver transplantation remain the only curative options for a small subset of patients. Few patients with HCC are diagnosed early enough to ...
Ezzat Tarek - - 2012
To investigate a dual labeling technique, which would enable real-time monitoring of transplanted embryonic stem cell (ESC) kinetics, as well as long-term tracking. Liver damage was induced in C57/BL6 male mice (n = 40) by acetaminophen (APAP) 300 mg/kg administered intraperitoneally. Green fluorescence protein (GFP) positive C57/BL6 mouse ESCs were ...
Hao Xiao-Wen - - 2012
To investigate the expression and methylation status of the secreted frizzled-related protein 2 (SFRP2) in esophageal squamous cell carcinoma (ESCC) and explore its role in ESCC carcinogenesis. Seven ESCC cell lines (KYSE 30, KYSE150, KYSE410, KYSE510, EC109, EC9706 and TE-1) and one immortalized human esophageal epithelial cell line (Het-1A), 20 ...
Gong Yan - - 2012
To explore the potential risk factors related to gastrointestinal cancer in northern China. A total of 3314 cases of gastrointestinal cancer (esophageal, gastric, pancreatic and biliary) and 2223 controls (including healthy individuals, glioma and thyroid cancer) were analyzed by case-control study. Multivariable logistic regression analysis was applied to evaluate the ...
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