JCP: Communications http://scitation.aip.org/ JCP: Communications Estimation of molar absorptivities and pigment sizes for eumelanin and pheomelanin using femtosecond transient absorption spectroscopy http://link.aip.org/link/?JCP/131/181106/1&agg=rss Ivan R. Piletic, Thomas E. Matthews, and Warren S. Warren<br/> 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. Thermodynamic consistency of energy and virial routes: An exact proof within the linearized DebyeHuckel theory http://link.aip.org/link/?JCP/131/181105/1&agg=rss Andres Santos, Riccardo Fantoni, and Achille Giacometti<br/> 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. Optimization of the residence time of a Brownian particle in a spherical subdomain http://link.aip.org/link/?JCP/131/181104/1&agg=rss O. Benichou and R. Voituriez<br/> 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. Towards quantum mechanical description of the unconventional mass-dependent isotope effect in ozone: Resonance recombination in the strong collision approximation http://link.aip.org/link/?JCP/131/181103/1&agg=rss S. Yu. Grebenshchikov and R. Schinke<br/> 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. Collision-induced absorption at wavelengths near 5 [mu]m by dense hydrogen gas http://link.aip.org/link/?JCP/131/181102/1&agg=rss Martin Abel, Lothar Frommhold, and Magnus Gustafsson<br/> 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. Robust quantization of a molecular motor motion in a stochastic environment http://link.aip.org/link/?JCP/131/181101/1&agg=rss V. Y. Chernyak and N. A. Sinitsyn<br/> 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. The role of the exchange in the embedding electrostatic potential for the fragment molecular orbital method http://link.aip.org/link/?JCP/131/171106/1&agg=rss Dmitri G. Fedorov and Kazuo Kitaura<!--orlang--> (&#x5317;&#x6D66;&#x548C;&#x592B;)<!--orlang--><br/> We have examined the role of the exchange in describing the electrostatic potential in the fragment molecular orbital method and showed that it should be included in the total Fock matrix to obtain an accurate one-electron spectrum; however, adding it to the Fock matrices of individual fragments and ... [J. Chem. Phys. 131, 171106 (2009)] published Fri Nov 6, 2009. Vibrational spectroscopy of neutral silicon clusters via far-IR-VUV two color ionization http://link.aip.org/link/?JCP/131/171105/1&agg=rss Andre Fielicke, Jonathan T. Lyon, Marko Haertelt, Gerard Meijer, Pieterjan Claes et al.<br/> Tunable far-infrared-vacuum-ultraviolet two color ionization is used to obtain vibrational spectra of neutral silicon clusters in the gas phase. Upon excitation with tunable infrared light prior to irradiation with UV photons we observe strong enhancements in the mass spectrometric signal of specifi ... [J. Chem. Phys. 131, 171105 (2009)] published Thu Nov 5, 2009. Molecular rotor dynamics influenced by the elastic modulus of polyethylene nanocomposites http://link.aip.org/link/?JCP/131/171104/1&agg=rss Ah-Young Jee, Haneul Kwon, and Minyung Lee<br/> We observed that the excited-state twisting motion of 3,3-diethyloxacarbocyanine in polymer nanocomposites (PNCs) depends strongly on the elastic modulus of medium. PNCs consist of low density polyethylene dispersed with surface-functionalized nanodiamonds with various alkyl groups. The mechanical p ... [J. Chem. Phys. 131, 171104 (2009)] published Thu Nov 5, 2009. Universal perturbative explicitly correlated basis set incompleteness correction http://link.aip.org/link/?JCP/131/171103/1&agg=rss Martin Torheyden and Edward F. Valeev<br/> Basis set incompleteness error for an arbitrary approximate electronic wave function is robustly reduced using a second-order perturbative correction into a basis of explicitly correlated, internally contracted geminal functions. The Hylleraas functional for the second-order energy correction is eva ... [J. Chem. Phys. 131, 171103 (2009)] published Wed Nov 4, 2009. Nonequilibrium Fock space for the electron transport problem http://link.aip.org/link/?JCP/131/171102/1&agg=rss D. S. Kosov<br/> Based on the formalism of thermofield dynamics we propose a concept of nonequilibrium Fock space and nonequilibrium quasiparticles for quantum many-body system in nonequilibrium steady state. We develop a general theory as well as demonstrate the utility of the approach on the example of electron tr ... [J. Chem. Phys. 131, 171102 (2009)] published Tue Nov 3, 2009. A least-constraint principle for population dynamics and reaction kinetics: Modeling entropy-controlled chemical hypercycles http://link.aip.org/link/?JCP/131/171101/1&agg=rss Denis Horvath and Gerald R. Kneller<br/> In this paper, we investigate the treatment of constraints in rate equations describing the temporal evolution of biological populations or chemical reactions. We present a formulation for arbitrary holonomic and linear nonholonomic constraints which ensures the positivity of the dynamical variables ... [J. Chem. Phys. 131, 171101 (2009)] published Mon Nov 2, 2009. The stiffness of a fully stretched polyethylene chain: A Raman jet spectroscopy extrapolation http://link.aip.org/link/?JCP/131/161108/1&agg=rss Tobias N. Wassermann, Jonas Thelemann, Philipp Zielke, and Martin A. Suhm<br/> Linear alkanes with n=516 C-atoms are partially relaxed into their stretched all-trans conformation by supersonic jet expansion. Their longitudinal acoustic modes are identified by spontaneous Raman scattering and deperturbed from transverse bending mode components and Fermi resonance with combinati ... [J. Chem. Phys. 131, 161108 (2009)] published Thu Oct 29, 2009. Observation of buried water molecules in phospholipid membranes by surface sum-frequency generation spectroscopy http://link.aip.org/link/?JCP/131/161107/1&agg=rss Maria Sovago, Erik Vartiainen, and Mischa Bonn<br/> We investigate the structure and orientation of water molecules at the water-lipid interface, using vibrational sum-frequency generation in conjunction with a maximum entropy phase retrieval method. We find that interfacial water molecules have an orientation opposite to that predicted by electrosta ... [J. Chem. Phys. 131, 161107 (2009)] published Thu Oct 29, 2009. Spatial updating in the great grand canonical ensemble http://link.aip.org/link/?JCP/131/161106/1&agg=rss G. Orkoulas and Daniel P. Noon<br/> In spatial updating grand canonical Monte Carlo, particle transfers are implemented by examining the local environment around a point in space. In the present work, these algorithms are extended to very high densities by allowing the volume to fluctuate, thus forming a great grand canonical ensemble ... [J. Chem. Phys. 131, 161106 (2009)] published Tue Oct 27, 2009. Ubiquitous T-shaped isomers of OCS-hydrocarbon van der Waals complexes http://link.aip.org/link/?JCP/131/161105/1&agg=rss J. Norooz Oliaee, M. Dehghany, Mahin Afshari, N. Moazzen-Ahmadi, and A. R. W. McKellar<br/> Many weakly bound OCS-hydrocarbon complexes exhibit a relatively simple rotation-vibration band, characteristic of a T-shaped structure, which is redshifted (by 512 cm) from the OCS monomer nu frequency. Spectra of OCS with seven chain and ring hydrocarbons are described here. They allow a straight ... [J. Chem. Phys. 131, 161105 (2009)] published Tue Oct 27, 2009. Grand potential in thermodynamics of solid bodies and surfaces http://link.aip.org/link/?JCP/131/161104/1&agg=rss A. I. Rusanov, A. K. Shchekin, and D. V. Tatyanenko<br/> Using the chemical potential of a solid in a dissolved state or the corresponding component of the chemical potential tensor at equilibrium with the solution, a new concept of grand thermodynamic potential for solids has been suggested. This allows generalizing the definition of Gibbs' quantity sigm ... [J. Chem. Phys. 131, 161104 (2009)] published Mon Oct 26, 2009. Hydrophobic effects on multivalent-salt-induced self-condensation of DNA http://link.aip.org/link/?JCP/131/161103/1&agg=rss Tomonari Sumi, Chiaki Suzuki, and Hideo Sekino<br/> Hydrophobic effects on multivalent-salt-induced self-condensation of a single polyelectrolyte chain such as DNA are investigated through a multiscale coarse-grained simulation based on density functional theory. We show that the water-mediated hydrophobic effect that was enhanced by hydration of mul ... [J. Chem. Phys. 131, 161103 (2009)] published Mon Oct 26, 2009. Laboratory observation of the valence anion of cyanoacetylene, a possible precursor for negative ions in space http://link.aip.org/link/?JCP/131/161102/1&agg=rss Daniel J. Goebbert, Dmitry Khuseynov, and Andrei Sanov<br/> Valence anions of cyanoacetylene, HCCCN, are synthesized by the 1,2-H abstraction reaction of O with acrylonitrile, HC=CHCN, while the competing 1,1-H channel of the same reaction yields the cyanovinylidene anions, CCHCN. The key to the formation of the elusive, adiabatically weakly bound HCCCN is t ... [J. Chem. Phys. 131, 161102 (2009)] published Fri Oct 23, 2009. Composition and concentration anomalies for structure and dynamics of Gaussian-core mixtures http://link.aip.org/link/?JCP/131/161101/1&agg=rss Mark J. Pond, William P. Krekelberg, Vincent K. Shen, Jeffrey R. Errington, and Thomas M. Truskett<br/> We report molecular dynamics simulation results for two-component fluid mixtures of Gaussian-core particles, focusing on how tracer diffusivities and static pair correlations depend on temperature, particle concentration, and composition. At low particle concentrations, these systems behave like sim ... [J. Chem. Phys. 131, 161101 (2009)] published Thu Oct 22, 2009. Density scaling in viscous liquids: From relaxation times to four-point susceptibilities http://link.aip.org/link/?JCP/131/151103/1&agg=rss D. Coslovich and C. M. Roland<br/> We present numerical calculations of a four-point dynamic susceptibility, chi(t), for the KobAndersen Lennard-Jones mixture as a function of temperature T and density rho. Over a relevant range of T and rho, the full t-dependence of chi(t) and thus the maximum in chi(t), which is proportional to the ... [J. Chem. Phys. 131, 151103 (2009)] published Mon Oct 19, 2009.