Journal of Chemical Physics: All Topics

Deliquescence and efflorescence of small particles

Robert McGraw and Ernie R. Lewis
We examine size-dependent deliquescence/efflorescence phase transformation for particles down to several nanometers in size. Thermodynamic properties of inorganic salt particles, coated with aqueous solution layers of varying thickness and surrounded by vapor, are analyzed. A thin layer criterion (T ... [J. Chem. Phys. 131, 194705 (2009)] published Fri Nov 20, 2009.

Photochemistry of 3-hydroxyflavone inside superfluid helium nanodroplets

R. Lehnig, D. Pentlehner, A. Vdovin, B. Dick, and A. Slenczka
3-hydroxyflavone is a prototype system for excited state intramolecular proton transfer which is one step of a closed loop photocycle. It was intensively studied for the bare molecule and for the influence of solvents. In the present paper this photocycle is investigated for 3-hydroxyflavone and som ... [J. Chem. Phys. 131, 194307 (2009)] published Fri Nov 20, 2009.

Electronic photodissociation spectra and decay pathways of gas-phase IrBr

Jesse C. Marcum and J. Mathias Weber
We report photodissociation action spectra for the dianion IrBr in the range of 1.085.6 eV. The photoproducts observed are IrBr, IrBr, IrBr and Br. Comparison of the action spectra to the aqueous absorption spectrum of KIrBr leads to the determination of solvatochromic shifts of between 0.02 and 0.1 ... [J. Chem. Phys. 131, 194309 (2009)] published Fri Nov 20, 2009.

Manipulating stimulated coherent anti-Stokes Raman spectroscopy signals by broad-band and narrow-band pulses

Saar Rahav, Oleksiy Roslyak, and Shaul Mukamel
A transition-amplitude based representation of heterodyne detected coherent anti-Stokes Raman signals is used to separate them into a parametric component that involves no change in the material and dissipative processes associated with various transitions between states. Qualitatively different con ... [J. Chem. Phys. 131, 194510 (2009)] published Fri Nov 20, 2009.

Extrapolating MP2 and CCSD explicitly correlated correlation energies to the complete basis set limit with first and second row correlation consistent basis sets

J. Grant Hill, Kirk A. Peterson, Gerald Knizia, and Hans-Joachim Werner
Accurate extrapolation to the complete basis set (CBS) limit of valence correlation energies calculated with explicitly correlated MP2-F12 and CCSD(T)-F12b methods have been investigated using a Schwenke-style approach for molecules containing both first and second row atoms. Extrapolation coefficie ... [J. Chem. Phys. 131, 194105 (2009)] published Fri Nov 20, 2009.

Oscillator strengths and line widths of dipole-allowed transitions in N between 86.0 and 89.7 nm

A. N. Heays, B. R. Lewis, G. Stark, K. Yoshino, Peter L. Smith et al.
Oscillator strengths of 23 electric-dipole-allowed bands of N in the 86.089.7 nm (111 480116 280 cm) region are reported from synchrotron-based photoabsorption measurements at an instrumental resolution of 6.5 x 10 nm (0.7 cm) full width at half maximum. The absorption spectrum comprises transit ... [J. Chem. Phys. 131, 194308 (2009)] published Fri Nov 20, 2009.

On nonadiabatic coupling vectors in time-dependent density functional theory

Ivano Tavernelli, Basile F. E. Curchod, and Ursula Rothlisberger
In this note, we show that the development for the calculation of nonadiabatic coupling vectors in the framework of TDDFT introduced by the authors in the series of recent publications [E. Tapavicza et al., Phys. Rev. Lett.98, 023001 (2007); I. Tavernelli et al., J. Chem. Phys.130, 124107 (2009)] is ... [J. Chem. Phys. 131, 196101 (2009)] published Fri Nov 20, 2009.

Molecular cooperativity in the dynamics of glass-forming systems: A new insight

L. Hong, P. D. Gujrati, V. N. Novikov, and A. P. Sokolov
The mechanism behind the steep slowing down of molecular motions upon approaching the glass transition remains a great puzzle. Most of the theories relate this mechanism to the cooperativity in molecular motion. In this work, we estimate the length scale of molecular cooperativity xi for many glass- ... [J. Chem. Phys. 131, 194511 (2009)] published Fri Nov 20, 2009.

Excited and ionized states of the ozone molecule with full triples coupled cluster methods

Monika Musial, Stanislaw A. Kucharski, Piotr Zerzucha, Tomasz Kuś, and Rodney J. Bartlett
The role of connected triple excitations in coupled cluster (CC) calculations of vertical excitation energies, ionization potentials, and the electron affinity of the ozone molecule is evaluated. The equation of motion (EOM) and Fock space (FS) multireference CC approaches with full triples have bee ... [J. Chem. Phys. 131, 194104 (2009)] published Fri Nov 20, 2009.

All-atom ab initio native structure prediction of a mixed fold (1FME): A comparison of structural and folding characteristics of various betabetaalpha miniproteins

Eunae Kim, Soonmin Jang, and Youngshang Pak
We performed an all-atom ab initio native structure prediction of 1FME, which is one of the computationally challenging mixed fold betabetaalpha miniproteins, by combining a novel conformational search algorithm (multiplexed Q-replica exchange molecular dynamics scheme) with a well-balanced all-atom ... [J. Chem. Phys. 131, 195102 (2009)] published Thu Nov 19, 2009.

A molecular dynamics study of the influence of ionic charge distribution on the dynamics of a molten salt

Hualin Li and Mark N. Kobrak
The distribution of charge in an ion of a fused salt is known to be an important determinant of liquid dynamics. However, the details of this relationship remain poorly understood. We present the results of molecular dynamics simulations on a model molten salt system and show that changes in the dis ... [J. Chem. Phys. 131, 194507 (2009)] published Thu Nov 19, 2009.

Spin-locking of half-integer quadrupolar nuclei in nuclear magnetic resonance of solids: Second-order quadrupolar and resonance offset effects

Sharon E. Ashbrook and Stephen Wimperis
Spin-locking of spin I=3/2 and I=5/2 nuclei in the presence of small resonance offset and second-order quadrupolar interactions has been investigated using both exact and approximate theoretical and experimental nuclear magnetic resonance (NMR) approaches. In the presence of second-order quadrupolar ... [J. Chem. Phys. 131, 194509 (2009)] published Thu Nov 19, 2009.

Publisher's Note: On the kinetics of the Al+Cl reaction: Cluster degradation in consecutive steps [J. Chem. Phys. 131, 174304 (2009)]

Matthias Olzmann, Ralf Burgert, and Hansgeorg Schnockel
Abstract not available. [J. Chem. Phys. 131, 199902 (2009)] published Thu Nov 19, 2009.

Swelling and collapse of polyelectrolyte gels in equilibrium with monovalent and divalent electrolyte solutions

De-Wei Yin, Monica Olvera de la Cruz, and Juan J. de Pablo
The swelling of polyelectrolyte (PE) gels by 1:1 and 2:1 salts is studied via osmotic ensemble Monte Carlo simulations at constant osmotic pressure and electrolyte chemical potential of a reservoir phase in equilibrium with a model PE network. Large molecular weight gels exhibit a remarkable swellin ... [J. Chem. Phys. 131, 194907 (2009)] published Thu Nov 19, 2009.

Ab initio molecular dynamics simulation of photoisomerization in azobenzene in the npi state

Yusuke Ootani, Kiminori Satoh, Akira Nakayama, Takeshi Noro, and Tetsuya Taketsugu
Photoisomerization mechanism of azobenzene in the lowest excited state S(npi) is investigated by ab initio molecular dynamics (AIMD) simulation with the RATTLE algorithm, based on the state-averaged complete active space self-consistent field method. AIMD simulations show that cis to trans isomeriza ... [J. Chem. Phys. 131, 194306 (2009)] published Thu Nov 19, 2009.

Localized soft modes and the supercooled liquid's irreversible passage through its configuration space

Asaph Widmer-Cooper, Heidi Perry, Peter Harrowell, and David R. Reichman
Using computer simulations, we show that the localized low frequency normal modes of a configuration in a supercooled liquid are strongly correlated with the irreversible structural reorganization of the particles within that configuration. Establishing this correlation constitutes the identificatio ... [J. Chem. Phys. 131, 194508 (2009)] published Thu Nov 19, 2009.

Publisher's Note: Transition state analysis of solid-solid transformations in nanocrystals [J. Chem. Phys. 131, 164116 (2009)]

Michael Grunwald and Christoph Dellago
Abstract not available. [J. Chem. Phys. 131, 199901 (2009)] published Thu Nov 19, 2009.

Stochastic bimodalities in deterministically monostable reversible chemical networks due to network topology reduction

Maxim N. Artyomov, Manikandan Mathur, Michael S. Samoilov, and Arup K. Chakraborty
Recently, stochastic simulations of networks of chemical reactions have shown distributions of steady states that are inconsistent with the steady state solutions of the corresponding deterministic ordinary differential equations. One such class of systems is comprised of networks that have irrevers ... [J. Chem. Phys. 131, 195103 (2009)] published Thu Nov 19, 2009.

Kinetics and morphology of cluster growth in a model of short-range attractive colloids

Siddique J. Khan, C. M. Sorensen, and A. Chakrabarti
We present results from detailed three-dimensional Brownian dynamics simulations of the self-assembly process in quenched short-range attractive colloids. Clusters obtained in the simulations range from dense faceted crystals to fractal aggregates which show ramified morphology on large length scale ... [J. Chem. Phys. 131, 194908 (2009)] published Thu Nov 19, 2009.

Reactions of simple aromatic heterocycles with niobium cluster ions (n<=30)

Britta Pfeffer, Stephanie Jaberg, and Gereon Niedner-Schatteburg
Prior work on benzene activation by size selected niobium cluster cations and anions of up to 30 atoms is extended systematically through studying aromatic poly- and heterocyclic molecules such as naphthalene, pyridine, thiophene, pyrrole, furan, and benzofuran. Naphthalene is found to act much like ... [J. Chem. Phys. 131, 194305 (2009)] published Thu Nov 19, 2009.

A new generic model potential for mesogenic systems: Square well line potential of variable range

Szabolcs Varga and Franz J. Vesely
A single-site pair potential is derived to approximate the linear n-site square well interaction. The resulting square well line (SWL) potential is analytical, fairly smooth, and reproduces the distance and orientation dependence of the multisite pair energy. It contains only three control parameter ... [J. Chem. Phys. 131, 194506 (2009)] published Wed Nov 18, 2009.

Interfering pathways in benzene: An analytical treatment

Thorsten Hansen, Gemma C. Solomon, David Q. Andrews, and Mark A. Ratner
The mechanism for off-resonant electron transport through small organic molecules in metallic junctions is predominantly coherent tunneling. Thus, new device functionalities based on quantum interference could be developed in the field of molecular electronics. We invoke a partitioning technique to ... [J. Chem. Phys. 131, 194704 (2009)] published Wed Nov 18, 2009.

Emergence of complex behavior in gelling systems starting from simple behavior of single clusters

A. Fierro, T. Abete, and A. Coniglio
A theoretical and numerically study of dynamical properties in the sol-gel transition is presented. In particular, the complex phenomenology observed experimentally and numerically in gelling systems is reproduced in the framework of percolation theory, under simple assumptions on the relaxation of ... [J. Chem. Phys. 131, 194906 (2009)] published Wed Nov 18, 2009.

Unimolecular decomposition of tetrazine-N-oxide based high nitrogen content energetic materials from excited electronic states

A. Bhattacharya, Y. Q. Guo, and E. R. Bernstein
Unimolecular excited electronic state decomposition of novel high nitrogen content energetic molecules, such as 3,3-azobis(6-amino-1,2,4,5-tetrazine)-mixed N-oxides (DAATO), 3-amino-6-chloro-1,2,4,5-tetrazine-2,4-dioxide (ACTO), and 3,6-diamino-1,2,4,5-tetrazine-1,4-dioxde (DATO), is investigated. A ... [J. Chem. Phys. 131, 194304 (2009)] published Wed Nov 18, 2009.

Effects of methanol on nanoparticle self-assembly at liquid-liquid interfaces: A molecular dynamics approach

Mingxiang Luo, Yanmei Song, and Lenore L. Dai
Molecular dynamics simulations have been performed to study the influence of methanol on the self-assembly of nanoparticles at liquid-liquid interfaces. The simulation shows that the methanol molecules, at low volume fraction, stay in the aqueous phase but with a preference of the water-trichloroeth ... [J. Chem. Phys. 131, 194703 (2009)] published Wed Nov 18, 2009.

Efficient calculation of the polarization induced by N coherent laser pulses

Maxim F. Gelin, Dassia Egorova, and Wolfgang Domcke
We have developed a novel method, the equation-of-motion phase-matching approach (EOM-PMA), for the calculation of the response of a quantum system to N coherent laser fields. The N-pulse EOM-PMA is limited to weak fields (its domain of validity is equivalent to the traditional nonlinear response fu ... [J. Chem. Phys. 131, 194103 (2009)] published Wed Nov 18, 2009.

Origin of translocation barriers for polyelectrolyte chains

Rajeev Kumar and M. Muthukumar
For single-file translocations of a charged macromolecule through a narrow pore, the crucial step of arrival of an end at the pore suffers from free energy barriers, arising from changes in intrachain electrostatic interaction, distribution of ionic clouds and solvent molecules, and conformational e ... [J. Chem. Phys. 131, 194903 (2009)] published Tue Nov 17, 2009.

Fluorescence depolarization in poly[2-methoxy-5-((2-ethylhexyl)oxy)-1,4-phenylenevinylene]: Sites versus eigenstates hopping

Jaykrishna Singh, Eric R. Bittner, David Beljonne, and Gregory D. Scholes
We report upon a theoretical study of singlet exciton migration and relaxation within a model conjugated polymer chain. Starting from poly[2-methoxy-5-((2-ethylhexyl)oxy)-1,4-phenylenevinylene] polymer chains, we assume that the pi-conjugation is disrupted by conformational disorder of the chain its ... [J. Chem. Phys. 131, 194905 (2009)] published Tue Nov 17, 2009.

Multiconfiguration time-dependent Hartree and classical dynamics studies of the photodissociation of HF and HCl molecules adsorbed on ice: Extension to three dimensions

S. Woittequand, C. Toubin, M. Monnerville, S. Briquez, B. Pouilly et al.
The 3D photodissociation dynamics of HCl and HF molecules adsorbed on ice is studied by quantum and classical simulations. The quantum calculations are carried out with the multiconfiguration time-dependent Hartree (MCTDH) approach. Dynamical observables like angular distributions in the momentum sp ... [J. Chem. Phys. 131, 194303 (2009)] published Tue Nov 17, 2009.

Free energy landscape for the translocation of polymer through an interacting pore

Li-Zhen Sun, Wei-Ping Cao, and Meng-Bo Luo
Free energy landscapes for polymer chain translocating through an interacting pore are calculated by using exact enumeration method. A potential barrier exists at weak attractive or repulsive polymer-pore interaction and it changes to a potential well with the increase in the attraction. The result ... [J. Chem. Phys. 131, 194904 (2009)] published Tue Nov 17, 2009.

Stability of binary mixtures in electric field gradients

Sela Samin and Yoav Tsori
We consider the influence of electric field gradients on the phase behavior of nonpolar binary mixtures. Small fields give rise to smooth composition profiles, whereas large enough fields lead to a phase-separation transition. The critical field for demixing as well as the equilibrium phase-separati ... [J. Chem. Phys. 131, 194102 (2009)] published Tue Nov 17, 2009.

A theoretical basis for spontaneous polarization transfer in non-hydrogenative parahydrogen-induced polarization

Ralph W. Adams, Simon B. Duckett, Richard A. Green, David C. Williamson, and Gary G. R. Green
When parahydrogen adds to a metal template containing a substrate of interest, the substrate and parahydrogen become coupled, and polarization is shared between the two without the incorporation of the parahydrogen into the substrate. A mechanism for this polarization transfer is presented in which ... [J. Chem. Phys. 131, 194505 (2009)] published Mon Nov 16, 2009.

Electronic relaxation dynamics in large anionic water clusters: (HO) and (DO) (n=25200)

Graham B. Griffin, Ryan M. Young, Oli T. Ehrler, and Daniel M. Neumark
Electronic relaxation dynamics subsequent to s-->p excitation of the excess electron in large anionic water clusters, (HO) and (DO) with 25<=n<=200, were investigated using time-resolved photoelectron imaging. Experimental improvements have enabled considerably larger clusters to be probed than in p ... [J. Chem. Phys. 131, 194302 (2009)] published Mon Nov 16, 2009.

Pressure dependence of the large-scale structure of water

A. Cunsolo, F. Formisano, C. Ferrero, F. Bencivenga, and S. Finet
We report on small-angle x-ray scattering measurements on liquid water aimed at characterizing the pressure evolution of its large-scale structure. Diffraction profiles have been fitted assuming a Lorentzian dependence on the exchanged momentum. As a result, we observe an anomalous behavior of the d ... [J. Chem. Phys. 131, 194502 (2009)] published Mon Nov 16, 2009.

Numerical determination of the exponents controlling the relationship between time, length, and temperature in glass-forming liquids

Chiara Cammarota, Andrea Cavagna, Giacomo Gradenigo, Tomas S. Grigera, and Paolo Verrocchio
There is a certain consensus that the very fast growth of the relaxation time tau occurring in glass-forming liquids on lowering the temperature must be due to the thermally activated rearrangement of correlated regions of growing size. Even though measuring the size of these regions has defied scie ... [J. Chem. Phys. 131, 194901 (2009)] published Mon Nov 16, 2009.

Multiplet splittings and intensities of fine structure components of the Q(0)H+S(0)N transition in a solid parahydrogen matrix

Adya P. Mishra and Param Jeet Singh
A comprehensive analysis of theoretical multiplet splittings and intensities of the fine structure components of the Q(0)H+S(0)N transition in a solid parahydrogen crystal is presented. The consideration of higher order anisotropic term responsible for splittings is essential to explain the observed ... [J. Chem. Phys. 131, 194503 (2009)] published Mon Nov 16, 2009.

Laser spectroscopy of NiI: New electronic states and hyperfine structure

A. S.-C. Cheung, H. F. Pang, W. S. Tam, and J. W.-H. Leung
Two new electronic transition systems, namely, the [14.0]Phi-X Delta and the [15.7]Phi-X Delta transitions were observed and analyzed using laser vaporization/reaction supersonic free jet expansion and high resolution laser induced fluorescence spectroscopy. In addition, the (v, 0) bands with v=610 ... [J. Chem. Phys. 131, 194301 (2009)] published Mon Nov 16, 2009.

Dynamic rheology of sphere- and rod-based magnetorheological fluids

J. de Vicente, J. P. Segovia-Gutierrez, E. Andablo-Reyes, F. Vereda, and R. Hidalgo-Alvarez
The effect of particle shape in the small amplitude oscillatory shear behavior of magnetorheological (MR) fluids is investigated from zero magnetic field strengths up to 800 kA/m. Two types of MR fluids are studied: the first system is prepared with spherical particles and a second system is prepare ... [J. Chem. Phys. 131, 194902 (2009)] published Mon Nov 16, 2009.

The transition state transit time of WW domain folding is controlled by energy landscape roughness

Feng Liu, Marcelo Nakaema, and Martin Gruebele
Protein folding barriers can be so low that a substantial protein population diffusing in the transition state region can be detected. The very fast kinetic phase contributed by transition state transit is the molecular phase. We detect the molecular phase of the beta-sheet protein FiP35 from 60 to ... [J. Chem. Phys. 131, 195101 (2009)] published Mon Nov 16, 2009.

Improvement of the ab initio embedded cluster method for luminescence properties of doped materials by taking into account impurity induced distortions: The example of YO:Bi

Florent Real, Belen Ordejon, Valerie Vallet, Jean-Pierre Flament, and Joel Schamps
New ab initio embedded-cluster calculations devoted to simulating the electronic spectroscopy of Bi impurities in YO sesquioxide for substitutions in either S or C cationic sites have been carried out taking special care of the quality of the environment. A considerable quantitative improvement with ... [J. Chem. Phys. 131, 194501 (2009)] published Mon Nov 16, 2009.

Stacking of polycyclic aromatic hydrocarbons as prototype for graphene multilayers, studied using density functional theory augmented with a dispersion term

C. Feng, C. S. Lin, W. Fan, R. Q. Zhang, and M. A. Van Hove
The interlayer pi-pi interaction between finite-size models of graphene sheets was investigated by using a density functional theory method, augmented with an empirical R term for the description of long-range dispersive interaction; these were calibrated by studying the pi-pi interaction between va ... [J. Chem. Phys. 131, 194702 (2009)] published Mon Nov 16, 2009.

X-ray absorption spectroscopy of biomimetic dye molecules for solar cells

Peter L. Cook, Xiaosong Liu, Wanli Yang, and F. J. Himpsel
Dye-sensitized solar cells are potentially inexpensive alternatives to traditional semiconductor solar cells. In order to optimize dyes for solar cells we systematically investigate the electronic structure of a variety of porphyrins and phthalocyanines. As a biological model system we use the heme ... [J. Chem. Phys. 131, 194701 (2009)] published Mon Nov 16, 2009.

Theory for the three-dimensional Mercedes-Benz model of water

Alan Bizjak, Tomaz Urbic, Vojko Vlachy, and Ken A. Dill
The two-dimensional Mercedes-Benz (MB) model of water has been widely studied, both by Monte Carlo simulations and by integral equation methods. Here, we study the three-dimensional (3D) MB model. We treat water as spheres that interact through Lennard-Jones potentials and through a tetrahedral Gaus ... [J. Chem. Phys. 131, 194504 (2009)] published Mon Nov 16, 2009.

An optimized full-configuration-interaction nuclear orbital approach to a hard-core interaction problem: Application to (He)Cl(B) clusters (N<=4)

M. P. de Lara-Castells, P. Villarreal, G. Delgado-Barrio, and A. O. Mitrushchenkov
An efficient full-configuration-interaction nuclear orbital treatment has been recently developed as a benchmark quantum-chemistry-like method to calculate ground and excited solvent energies and wave functions in small doped DeltaE clusters (N<=4) [M. P. de Lara-Castells, G. Delgado-Barrio, P. Vill ... [J. Chem. Phys. 131, 194101 (2009)] published Mon Nov 16, 2009.

Statistical mechanical theory for nonequilibrium systems. X. Nonequilibrium phase transitions

Phil Attard
A general theory for the stability and coexistence of nonequilibrium phases is formulated. An integral formulation of the second entropy is given, the functional maximization of which yields nonlinear hydrodynamics. RayleighBenard convection is analyzed, and analytic approximations are obtained for ... [J. Chem. Phys. 131, 184509 (2009)] published Fri Nov 13, 2009.

Calculation of the static electronic second hyperpolarizability or chi tensor of three-dimensional periodic compounds with a local basis set

Roberto Orlando, Mauro Ferrero, Michel Rerat, Bernard Kirtman, and Roberto Dovesi
The coupled perturbed HartreeFock (CPHF) method for evaluating static first (beta) and second (gamma) hyperpolarizability tensors of periodic systems has recently been implemented in the CRYSTAL code [Bishop et al., J. Chem. Phys. 114, 7633 (2001)]. We develop here an efficient and accurate computat ... [J. Chem. Phys. 131, 184105 (2009)] published Fri Nov 13, 2009.

Infrared spectra of protonated polycyclic aromatic hydrocarbon molecules: Azulene

Dawei Zhao, Judith Langer, Jos Oomens, and Otto Dopfer
The infrared (IR) spectrum of protonated azulene (AzuH, CH) has been measured in the fingerprint range (6001800 cm) by means of IR multiple photon dissociation (IRMPD) spectroscopy in a Fourier transform ion cyclotron resonance mass spectrometer equipped with an electrospray ionization source using ... [J. Chem. Phys. 131, 184307 (2009)] published Fri Nov 13, 2009.

Ions in hyaluronic acid solutions

Ferenc Horkay, Peter J. Basser, David J. Londono, Anne-Marie Hecht, and Erik Geissler
Hyaluronic acid (HA) is an anionic biopolymer that is almost ubiquitous in biological tissues. An attempt is made to determine the dominant features that account for both its abundance and its multifunctional role, and which set it apart from other types of biopolymers. A combination of osmotic and ... [J. Chem. Phys. 131, 184902 (2009)] published Fri Nov 13, 2009.

Spin-orbit effects on the photophysical properties of Ru(bpy)

Jean-Louis Heully, Fabienne Alary, and Martial Boggio-Pasqua
We present in this article a detailed study of the photophysics of the Ru(bpy) complex based on a formalism using density functional theory and an a posteriori treatment of the spin-orbit coupling. The absorption and emission spectra were computed and a very good agreement was obtained with the avai ... [J. Chem. Phys. 131, 184308 (2009)] published Fri Nov 13, 2009.

Estimation of molar absorptivities and pigment sizes for eumelanin and pheomelanin using femtosecond transient absorption spectroscopy

Ivan R. Piletic, Thomas E. Matthews, and Warren S. Warren
Fundamental optical and structural properties of melanins are not well understood due to their poor solubility characteristics and the chemical disorder present during biomolecular synthesis. We apply nonlinear transient absorption spectroscopy to quantify molar absorptivities for eumelanin and pheo ... [J. Chem. Phys. 131, 181106 (2009)] published Fri Nov 13, 2009.

How to calculate H better

Michele Pavanello, Wei-Cheng Tung, and Ludwik Adamowicz
Efficient optimization of the basis set is key to achieving a very high accuracy in variational calculations of molecular systems employing basis functions that are explicitly dependent on the interelectron distances. In this work we present a method for a systematic enlargement of basis sets of exp ... [J. Chem. Phys. 131, 184106 (2009)] published Fri Nov 13, 2009.

High sensitivity of O NMR to p-d hybridization in transition metal perovskites: First principles calculations of large anisotropic chemical shielding

Daniel L. Pechkis, Eric J. Walter, and Henry Krakauer
A first principles embedded cluster approach is used to calculate O chemical shielding tensors, sigma-hat, in prototypical transition metal oxide ABO perovskite crystals. Our principal findings are (1) a large anisotropy of sigma-hat between deshielded sigma~=sigma and shielded sigma components (z a ... [J. Chem. Phys. 131, 184511 (2009)] published Fri Nov 13, 2009.

Evolution of excess wing and beta-process in simple glass formers

Catalin Gainaru, Robert Kahlau, Ernst A. Rossler, and Roland Bohmer
Dielectric loss spectra of glass forming liquids are analyzed, with emphasis on systems for which a peak due to a secondary relaxation is not immediately obvious. Thus, glass formers are considered for which the high-frequency flank of the alpha-relaxation peak appears to be dominated by a so-called ... [J. Chem. Phys. 131, 184510 (2009)] published Fri Nov 13, 2009.

The thermodynamic and ground state properties of the TIP4P water octamer

E. Asare, A-R. Musah, E. Curotto, David L. Freeman, and J. D. Doll
Several stochastic simulations of the TIP4P [W. L. Jorgensen, J. Chandrasekhar, J. D. Madura, R. W. Impey, and M. L. Klein, J. Chem. Phys. 79, 926 (1983)] water octamer are performed. Use is made of the stereographic projection path integral and the Green's function stereographic projection diffusio ... [J. Chem. Phys. 131, 184508 (2009)] published Fri Nov 13, 2009.

Thermodynamic consistency of energy and virial routes: An exact proof within the linearized DebyeHuckel theory

Andres Santos, Riccardo Fantoni, and Achille Giacometti
The linearized DebyeHuckel theory for liquid state is shown to provide thermodynamically consistent virial and energy routes for any potential and for any dimensionality. The importance of this result for bounded potentials is discussed. ... [J. Chem. Phys. 131, 181105 (2009)] published Fri Nov 13, 2009.

Energy and density analysis of the H molecule from the united atom to dissociation: The Sigma and Sigma states

Giorgina Corongiu and Enrico Clementi
The first 14 Sigma and the first 15 Sigma states of the H molecule are computed with full configuration interaction both from HartreeFock molecular orbitals and HeitlerLondon atomic orbitals within the BornOppenheimer approximation, following recent studies for the Sigma and Sigma manifolds [Corongi ... [J. Chem. Phys. 131, 184306 (2009)] published Thu Nov 12, 2009.

Solid-liquid phase equilibria of the Gaussian core model fluid

Peter Mausbach, Alauddin Ahmed, and Richard J. Sadus
The solid-liquid phase equilibria of the Gaussian core model are determined using the GWTS [J. Ge, G.-W. Wu, B. D. Todd, and R. J. Sadus, J. Chem. Phys. 119, 11017 (2003)] algorithm, which combines equilibrium and nonequilibrium molecular dynamics simulations. This is the first reported use of the G ... [J. Chem. Phys. 131, 184507 (2009)] published Thu Nov 12, 2009.

Structural aging and stiction dynamics in confined liquid films

Shinji Yamada
The static friction (stiction) of the molecularly thin films of an irregularly shaped molecule 1,3-dimethylbutyl octyl ether (DBOE) confined between mica surfaces was investigated using the surface forces apparatus. Stop-start experiments were carried out and the stiction spike was measured as a fun ... [J. Chem. Phys. 131, 184708 (2009)] published Thu Nov 12, 2009.

Grand canonical steady-state simulation of nucleation

Martin Horsch and Jadran Vrabec
Grand canonical molecular dynamics (GCMD) is applied to the nucleation process in a metastable phase near the spinodal, where nucleation occurs almost instantaneously and is limited to a very short time interval. With a variant of Maxwell's demon, proposed by McDonald [Am. J. Phys. 31, 31 (1963)], a ... [J. Chem. Phys. 131, 184104 (2009)] published Thu Nov 12, 2009.

An efficient tool for modeling and predicting fluid flow in nanochannels

Samad Ahadian, Hiroshi Mizuseki, and Yoshiyuki Kawazoe
Molecular dynamics simulations were performed to evaluate the penetration of two different fluids (i.e., a Lennard-Jones fluid and a polymer) through a designed nanochannel. For both fluids, the length of permeation as a function of time was recorded for various wall-fluid interactions. A novel meth ... [J. Chem. Phys. 131, 184506 (2009)] published Thu Nov 12, 2009.

Optimization of the residence time of a Brownian particle in a spherical subdomain

O. Benichou and R. Voituriez
In this communication, we show that the residence time of a Brownian particle, defined as the cumulative time spent in a given region of space, can be optimized as a function of the diffusion coefficient. We discuss the relevance of this effect to several schematic experimental situations classified ... [J. Chem. Phys. 131, 181104 (2009)] published Thu Nov 12, 2009.

Super-Poissonian statistics of on-off jumps in blinking fluorescence of single molecules

I. S. Osad'ko
Blinking fluorescence of a single guest molecule embedded in a polymer matrix and excited by cw laser light is considered. Such fluorescence exhibits quantum jumps from bright on-intervals to dark off-intervals, i.e., so-called on-->off jumps. A system with one type of on-intervals and with two type ... [J. Chem. Phys. 131, 185101 (2009)] published Wed Nov 11, 2009.

Reactivity of aluminum cluster anions with ammonia: Selective etching of Al and Al

Andrej Grubisic, Xiang Li, Gerd Gantefoer, Kit H. Bowen, Hansgeorg Schnockel et al.
Reactivity of aluminum cluster anions toward ammonia was studied via mass spectrometry. Highly selective etching of Al and Al was observed at low concentrations of ammonia. However, at sufficiently high concentrations of ammonia, all other sizes of aluminum cluster anions, except for Al, were also o ... [J. Chem. Phys. 131, 184305 (2009)] published Wed Nov 11, 2009.

Isotope effects in liquid water by infrared spectroscopy. III. HO and DO spectra from 6000 to 0 cm

Jean-Joseph Max and Camille Chapados
The infrared spectra (IR) of pure liquid light (HO) and heavy (DO) water were obtained with attenuated total reflection (ATR) and transmission measurements in the mid-IR and far-IR. With these and with other values obtained from the literature, the real (n) and imaginary parts (k) of the refractive ... [J. Chem. Phys. 131, 184505 (2009)] published Wed Nov 11, 2009.

Symmetry breaking of the density distribution of a quantum fluid in a nanoslit

Gersh O. Berim and Eli Ruckenstein
The phenomenon of symmetry breaking (SB) of the fluid density distribution in a slit between parallel identical solid walls examined previously for a classical fluid (argon) [G. O. Berim and E. Ruckenstein, J. Chem. Phys. 126, 124503 (2007)] is examined for a quantum fluid (He) on the basis of a non ... [J. Chem. Phys. 131, 184707 (2009)] published Wed Nov 11, 2009.

Intermolecular proton-transfer in acetic acid clusters induced by vacuum-ultraviolet photoionization

Keisuke Ohta, Yoshiyuki Matsuda, Naohiko Mikami, and Asuka Fujii
Infrared (IR) spectroscopy based on vacuum-ultraviolet one-photon ionization detection was carried out to investigate geometric structures of neutral and cationic clusters of acetic acid: (CHCOOH), CHCOOHCHOH, and CHCOOHHO. All the neutral clusters have cyclic-type intermolecular structures, in whic ... [J. Chem. Phys. 131, 184304 (2009)] published Wed Nov 11, 2009.

Scaling the dynamics of orientationally disordered mixed crystals

M. Romanini, J. C. Martinez-Garcia, J. Ll. Tamarit, S. J. Rzoska, M. Barrio et al.
The evolution of the primary relaxation time of orientationally disordered (OD) mixed crystals [(CH)C(CHOH)][(CH)C(CHOH)], with 0

Electrostatic correlations at the Stern layer: Physics or chemistry?

A. Travesset and S. Vangaveti
We introduce a minimal free energy describing the interaction of charged groups and counterions including both classical electrostatic and specific interactions. The predictions of the model are compared against the standard model for describing ions next to charged interfaces, consisting of Poisson ... [J. Chem. Phys. 131, 185102 (2009)] published Wed Nov 11, 2009.

Nematic and smectic ordering in a system of two-dimensional hard zigzag particles

Szabolcs Varga, Peter Gurin, Julio C. Armas-Perez, and Jacqueline Quintana-H
The orientational and positional ordering of the two-dimensional system of hard zigzag particles has been investigated by means of Onsager theory. Analytical results are obtained for the transition densities of the isotropic-nematic and the nematic-smectic phase transitions. It is shown that the sta ... [J. Chem. Phys. 131, 184901 (2009)] published Wed Nov 11, 2009.

High-resolution cavity ringdown spectroscopy of the jet-cooled ethyl peroxy radical CHO

Gabriel M. P. Just, Patrick Rupper, Terry A. Miller, and W. Leo Meerts
We have recorded high resolution, partially rotationally resolved, jet-cooled cavity ringdown spectra of the origin band of the AX-tilde electronic transition of both the G and T conformers of the perproteo and perdeutero isotopologues of the ethyl peroxy radical, CHO. This transition, located in th ... [J. Chem. Phys. 131, 184303 (2009)] published Wed Nov 11, 2009.

Towards quantum mechanical description of the unconventional mass-dependent isotope effect in ozone: Resonance recombination in the strong collision approximation

S. Yu. Grebenshchikov and R. Schinke
The dependence of ozone recombination rate on the masses of oxygen isotopes is examined in the strong collision approximation by means of quantum mechanical calculations of resonance spectra of several rotating isotopomers. The measured DeltaZPE effect and its temperature dependence can be reconstru ... [J. Chem. Phys. 131, 181103 (2009)] published Tue Nov 10, 2009.

Probing CO bond activation on gas-phase transition metal clusters: Infrared multiple photon dissociation spectroscopy of Fe, Ru, Re, and W cluster CO complexes

Jonathan T. Lyon, Philipp Gruene, Andre Fielicke, Gerard Meijer, and David M. Rayner
The binding of carbon monoxide to iron, ruthenium, rhenium, and tungsten clusters is studied by means of infrared multiple photon dissociation spectroscopy. The CO stretching mode is used to probe the interaction of the CO molecule with the metal clusters and thereby the activation of the CO bond. C ... [J. Chem. Phys. 131, 184706 (2009)] published Tue Nov 10, 2009.

Molecular dynamics simulation of cooling: Heat transfer from a photoexcited peptide to the solvent

Sang-Min Park, Phuong H. Nguyen, and Gerhard Stock
A systematic molecular dynamics (MD) simulation study of the photoinduced heat transfer from the model peptide N-methylacetamide (NMA) to various solvents is presented, which considers four types of solvent (water, dimethyl sulfoxide, chloroform, and carbon tetrachloride), and in total 24 different ... [J. Chem. Phys. 131, 184503 (2009)] published Tue Nov 10, 2009.

Effect of CO desorption and coadsorption with O on the phase diagram of a ZiffGulariBarshad model for the catalytic oxidation of CO

G. M. Buendia, E. Machado, and P. A. Rikvold
We study the effect of coadsorption of CO and O on a ZiffGulariBarshad model with CO desorption for the reaction CO+O-->CO on a catalytic surface. Coadsorption of CO at a surface site already occupied by an O is introduced by an EleyRideal-type mechanism that occurs with probability p, 0<=p<=1. We f ... [J. Chem. Phys. 131, 184704 (2009)] published Tue Nov 10, 2009.

Collision-induced absorption at wavelengths near 5 [mu]m by dense hydrogen gas

Martin Abel, Lothar Frommhold, and Magnus Gustafsson
Based on a recent ab initio interaction-induced dipole surface of collisionally interacting molecular hydrogen pairs HH, we compute the binary absorption coefficients at wavelengths near 5 [mu]m at temperatures of 77.5 and 297 K for comparison with existing laboratory measurements. We observe satis ... [J. Chem. Phys. 131, 181102 (2009)] published Tue Nov 10, 2009.

Quantum mechanical/molecular mechanical/continuum style solvation model: Linear response theory, variational treatment, and nuclear gradients

Hui Li
Linear response and variational treatment are formulated for HartreeFock (HF) and KohnSham density functional theory (DFT) methods and combined discrete-continuum solvation models that incorporate self-consistently induced dipoles and charges. Due to the variational treatment, analytic nuclear gradi ... [J. Chem. Phys. 131, 184103 (2009)] published Tue Nov 10, 2009.

Molecular dynamics simulations of glycine crystal-solution interface

Soumik Banerjee and Heiko Briesen
Glycine is an amino acid that has several applications in the pharmaceutical industry. Hence, growth of alpha-glycine crystals through solution crystallization is an important process. To gain a fundamental understanding of the seeded growth of alpha-glycine from aqueous solution, the (110) face of ... [J. Chem. Phys. 131, 184705 (2009)] published Tue Nov 10, 2009.

Robust quantization of a molecular motor motion in a stochastic environment

V. Y. Chernyak and N. A. Sinitsyn
We explore quantization of the response of a molecular motor to periodic modulation of control parameters. We formulate the pumping-quantization theorem (PQT) that identifies the conditions for robust integer quantized behavior of a periodically driven molecular machine. Implication of PQT on experi ... [J. Chem. Phys. 131, 181101 (2009)] published Tue Nov 10, 2009.

Capillary liquid bridges in atomic force microscopy: Formation, rupture, and hysteresis

Yumei Men, Xianren Zhang, and Wenchuan Wang
Atomic force microscopy (AFM) can work in a variety of environment with different humidities. When the tip of AFM approaches a sample, the measured adhesion force would be significantly affected by the presence of nanometer-sized liquid bridge. The formation and rupture of liquid bridges can occur e ... [J. Chem. Phys. 131, 184702 (2009)] published Mon Nov 9, 2009.

Role of Ag-doping in small transition metal clusters from first-principles simulations

S. F. Li, Zelun Shao, Shuli Han, Xinlian Xue, F. Wang et al.
First-principles calculations are used to systematically investigate the geometric and electronic structures of both pure TM (n=24) and Ag-modulated AgTM (n=24; 3d-transition metal (TM): from Sc to Cu; 4d-TM: from Y to Ag elements) clusters. Some new ground state structures are found for the pure TM ... [J. Chem. Phys. 131, 184301 (2009)] published Mon Nov 9, 2009.

Reverse dynamic calorimetry of a viscous ionic liquid

Wei Huang and Ranko Richert
We compare the time scale of thermal relaxation with that of the electric modulus in the deeply supercooled regime of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate. Thermal relaxation refers to the process of configurational temperatures of the slow degrees of freedom equilibratin ... [J. Chem. Phys. 131, 184501 (2009)] published Mon Nov 9, 2009.

Generalizations of the YoungLaplace equation for the pressure of a mechanically stable gas bubble in a soft elastic material

Saul Goldman
The YoungLaplace equation for the pressure of a mechanically stable gas bubble is generalized to include the effects of both surface tension and elastic forces of its surroundings. The latter are taken to be comprised of a soft isotropic material. Generalizations are derived for conditions of consta ... [J. Chem. Phys. 131, 184502 (2009)] published Mon Nov 9, 2009.

Non-Markovian quantum jumps in excitonic energy transfer

Patrick Rebentrost, Rupak Chakraborty, and Alan Aspuru-Guzik
We utilize the novel non-Markovian quantum jump (NMQJ) approach to stochastically simulate exciton dynamics derived from a time-convolutionless master equation. For relevant parameters and time scales, the time-dependent, oscillatory decoherence rates can have negative regions, a signature of non-Ma ... [J. Chem. Phys. 131, 184102 (2009)] published Mon Nov 9, 2009.

A photoelectron and double photoionization study of the valence electronic structure of 1,4-bromofluorobenzene

M. Elshakre, L. Storchi, T. Kloda, P. Linusson, F. Heijkenskjold et al.
Conventional photoelectron and time-of-flight photoelectron-photoelectron coincidence (TOF-PEPECO) spectra have been measured for the outer valence region of the 1,4-bromofluorobenzene molecule. The photoelectron spectra were recorded using HeIalpha radiation from a resonance source, and the TOF-PEP ... [J. Chem. Phys. 131, 184302 (2009)] published Mon Nov 9, 2009.

An empirical potential based quasicontinuum theory for structural prediction of water

A. V. Raghunathan and N. R. Aluru
An empirical potential based quasicontinuum theory (EQT) is proposed to predict the structure, concentration, and various potential profiles of water in confined environments. EQT seamlessly unifies the continuum theory given by the NernstPlanck equation and the atomistic theory governed by interato ... [J. Chem. Phys. 131, 184703 (2009)] published Mon Nov 9, 2009.

Buoyancy-driven convection around exothermic autocatalytic chemical fronts traveling horizontally in covered thin solution layers

L. Rongy and A. De Wit
Spatial variations of concentrations and temperature across exothermic chemical fronts can initiate buoyancy-driven convection. We investigate here theoretically the spatiotemporal dynamics arising from such a coupling between exothermic autocatalytic reactions, diffusion, and buoyancy-driven flows ... [J. Chem. Phys. 131, 184701 (2009)] published Mon Nov 9, 2009.

Nucleation in a Potts lattice gas model of crystallization from solution

Nathan Duff and Baron Peters
Nucleation from solution is important in many pharmaceutical crystallization, biomineralization, material synthesis, and self-assembly processes. Simulation methodology has progressed rapidly for studies of nucleation in pure component and implicit solvent systems; however little progress has been m ... [J. Chem. Phys. 131, 184101 (2009)] published Mon Nov 9, 2009.