Pradip Kr. Ghorai

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Atomistic molecular dynamics simulations are performed to study the stripelike patterns formed by phase separation of immiscible surfactants grafted on spherical surfaces. In previous work (Phys. ReV. Lett. 2007, 99, 226106), we showed that the formation of a striped phase for a mixture of two different length surfactants does not depend on the detailed(More)
Natural surfaces are often structured with nanometre-scale domains, yet a framework providing a quantitative understanding of how nanostructure affects interfacial energy, gamma(SL), is lacking. Conventional continuum thermodynamics treats gamma(SL) solely as a function of average composition, ignoring structure. Here we show that, when a surface has(More)
A combination of immiscible molecules in the ligand shell of a gold nanoparticle (NP) has been shown to phase separate into a rippled structure; this phase separation can be used to direct the assembly of the NPs into chains. Here we demonstrate that only NPs within a certain size range can form chains, and we conclude that the rippled morphology of the(More)
Natural surfaces are often structured with nanometre-scale domains, yet a framework providing a quantitative understanding of how nanostructure affects interfacial energy, γSL, is lacking. Conventional continuum thermodynamics treats γSL solely as a function of average composition, ignoring structure. Here we show that, when a surface has domains(More)
We develop a model of electron transfer reactions at conditions of nonergodicity when the time of solvent relaxation crosses the observation time window set up by the reaction rate. Solvent reorganization energy of intramolecular electron transfer in a charge-transfer molecule dissolved in water and acetonitrile is studied by molecular dynamics simulations(More)
We report the results of molecular dynamics simulations of the solvent reorganization energy of intramolecular electron transfer in a charge-transfer molecule dissolved in water and acetonitrile at varying temperatures. The simulations confirm the prediction of microscopic solvation theories of a positive reorganization entropy in polar solvents. The(More)
We perform atomistic and mesoscale simulations to explain the origin of experimentally observed stripelike patterns formed by immiscible ligands coadsorbed on the surfaces of gold and silver nanoparticles. We show that when the conformational entropy gained via this morphology is sufficient, microphase-separated stripelike patterns form. When the entropic(More)
This paper reports the results of Molecular Dynamics (MD) simulations of the solvent reorganization energy of electron transfer (ET) reactions in low-temperature solvents. Simulations are carried out for a model charge-transfer optical dye (p-nitroaniline) in SPC/E water in a range of temperatures down to the point of solvent ideal glass transition. We show(More)
Atomistic molecular dynamics (MD) simulations of self-assembled alkanethiol monolayers are performed to investigate the ligand shell organization of homoligand surfactants on spherical gold nanoparticle surfaces as a function of temperature, nanoparticle size, and ligand tail length. At high temperature, we show that the ligands orient randomly with respect(More)
We present a molecular-dynamics study of the solvent reorganization energy of electron transfer in supercooled water. We observe a sharp decrease of the reorganization energy at a temperature identified as the temperature of structural arrest due to cage effect as discussed by the mode coupling theory. Both the heat capacity and dielectric susceptibility of(More)
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