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Full-Text Articles in Physical Sciences and Mathematics
Radical Chemistry In A Femtosecond Laser Plasma: Photochemical Reduction Of Ag+ In Liquid Ammonia Solution, Victoria K. Meader, Mallory G. John, Laysa M. Frias Batista, Syeda Ahsan, Katharine M. Tibbetts
Radical Chemistry In A Femtosecond Laser Plasma: Photochemical Reduction Of Ag+ In Liquid Ammonia Solution, Victoria K. Meader, Mallory G. John, Laysa M. Frias Batista, Syeda Ahsan, Katharine M. Tibbetts
Chemistry Publications
Plasmas with dense concentrations of reactive species such as hydrated electrons and hydroxyl radicals are generated from focusing intense femtosecond laser pulses into aqueous media. These radical species can reduce metal ions such as Au3+ to form metal nanoparticles (NPs). However, the formation of H2O2 by the recombination of hydroxyl radicals inhibits the reduction of Ag+ through back-oxidation. This work has explored the control of hydroxyl radical chemistry in a femtosecond laser-generated plasma through the addition of liquid ammonia. The irradiation of liquid ammonia solutions resulted in a reaction between NH3 and OH·, forming peroxynitrite and ONOO−, and significantly reducing …
Electrokinetic Flow Of Aqueous Electrolyte In Amorphous Silica Nanotubes, Chris D. Daub, Natalie Cann, D. Bratko, Alenka Luzar
Electrokinetic Flow Of Aqueous Electrolyte In Amorphous Silica Nanotubes, Chris D. Daub, Natalie Cann, D. Bratko, Alenka Luzar
Chemistry Publications
We study the pressure-driven flow of aqueous NaCl in amorphous silica nanotubes using nonequilibrium molecular dynamics simulations featuring both polarizable and non-polarizable molecular models. Different pressures, electrolyte concentrations and pore sizes are examined. Our results indicate a flow that deviates considerably from the predictions of Poiseuille fluid mechanics. Due to preferential adsorption of the different ionic species by surface SiO! or SiOH groups, we find that a significant electric current is generated, but with opposite polarities using polarizable vs. fixed charge models for water and ions, emphasizing the need for careful parameterization in such complex systems. We also examine the …
Curvature Dependence Of The Effect Of Ionic Functionalization On The Attraction Among Nanoparticles In Dispersion, B. Shadrack Jabes, D. Bratko, Alenka Luzar
Curvature Dependence Of The Effect Of Ionic Functionalization On The Attraction Among Nanoparticles In Dispersion, B. Shadrack Jabes, D. Bratko, Alenka Luzar
Chemistry Publications
Solubilization of nanoparticles facilitates nanomaterial processing and enables new applications. An effective method to improve dispersibility in water is provided by ionic functionalization.We explore how the necessary extent of functionalization depends on the particle geometry. Using molecular dynamics/umbrella sampling simulations, we determine the effect of the solute curvature on solventaveraged interactions among ionizing graphitic nanoparticles in aqueous dispersion. We tune the hydrophilicity of molecular-brush coated fullerenes, carbon nanotubes, and graphane platelets by gradually replacing a fraction of the methyl end groups of the alkyl coating by the ionizing –COOK or –NH3Cl groups. To assess the change in nanoparticles’ dispersibility in …
Nucleation And Growth Of Gold Nanoparticles Initiated By Nanosecond And Femtosecond Laser Irradiation Of Aqueous [Aucl4]-, Collin Rodrigues, Julian A. Bobb, Mallory G. John, Sergey Fisenko, M. S. El-Shall, Katharine M. Tibbetts
Nucleation And Growth Of Gold Nanoparticles Initiated By Nanosecond And Femtosecond Laser Irradiation Of Aqueous [Aucl4]-, Collin Rodrigues, Julian A. Bobb, Mallory G. John, Sergey Fisenko, M. S. El-Shall, Katharine M. Tibbetts
Chemistry Publications
Irradiation of aqueous [AuCl4]with 532 nm nanosecond (ns) laser pulses produces monodisperse (PDI = 0.04) 5 nm Au nanoparticles (AuNPs) without any additives or capping agents via a plasmon- enhanced photothermal autocatalytic mechanism. Compared with 800 nm femtosecond (fs) laser pulses, the AuNP growth kinetics under ns laser irradiation follow the same autocatalytic rate law, but with a significantly lower sensitivity to laser pulse energy. The results are explained using a simple model for simulating heat transfer in liquid water and at the interface with AuNPs. While the extent of water superheating with the ns laser is smaller compared to …