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Francisco Alarcon - One of the best experts on this subject based on the ideXlab platform.

  • dissipative particle dynamics simulations of weak polyelectrolyte adsorption on charged and neutral surfaces as a function of the Degree of Ionization
    Soft Matter, 2013
    Co-Authors: Francisco Alarcon, Elias Perez, Gama A Goicochea
    Abstract:

    The influence of the chain Degree of Ionization on the adsorption of weak polyelectrolytes on neutral and on oppositely and likely charged surfaces is investigated, by means of Monte Carlo simulations with a mesoscopic interaction model known as dissipative particle dynamics. The electrostatic interactions are calculated using the three-dimensional Ewald sum method, with an appropriate modification for confined systems. Effective wall forces confine the linear polyelectrolytes, and electric charges on the surfaces are included. The solvent, which is included explicitly, has a fluctuating particle number. The results show that the polyelectrolytes adsorb onto both neutral and charged surfaces, with the adsorption regulated by the chain Degree of Ionization, being larger at lower Ionization Degrees, where polyelectrolytes are less charged. Furthermore, polyelectrolyte adsorption is strongly modulated by the counterions screening of surface charges. These findings are supported by predictions of adsorption isotherms with varying Ionization Degrees. We obtain also the surface force mediated by adsorbed polyelectrolytes, which is calculated for the first time as a function of Ionization Degree. The adsorption and surface force isotherms obtained for weak polyelectrolytes are found to reproduce main trends in experiments, whenever those results are available, and provide additional insight into the role played by the competitive adsorption of the counterions and polyelectrolytes on the surfaces.

  • dissipative particle dynamics simulations of weak polyelectrolyte adsorption on charged and neutral surfaces as a function of the Degree of Ionization
    arXiv: Biological Physics, 2012
    Co-Authors: Francisco Alarcon, Elias Perez, Gama A Goicochea
    Abstract:

    The influence of the chain Degree of Ionization on the adsorption of weak polyelectrolytes on neutral and on oppositely and likely charged surfaces is investigated for the first time, by means of Monte Carlo simulations with the mesoscopic interaction model known as dissipative particle dynamics. The electrostatic interactions are calculated using the three-dimensional Ewald sum method, with an appropriate modification for confined systems. Effective wall forces confine the linear polyelectrolytes, and electric charges on the surfaces are included. The solvent is included explicitly also and it is modeled as an athermal solvent for the polyelectrolytes. The number of solvent particles is allowed to fluctuate. The results show that the polyelectrolytes adsorb both onto neutral and charged surfaces, with the adsorption regulated by the chain Degree of Ionization, being larger at lower Ionization Degrees, where polyelectrolytes are less charged. Furthermore, polyelectrolyte adsorption is strongly modulated by the counterions screening of surface charge. These findings are supported with predictions of adsorption isotherms with varying Ionization Degree. We obtain also the surface force mediated by adsorbed polyelectrolytes, which is calculated for the first time as a function of Ionization Degree. The adsorption and surface force isotherms obtained for weak polyelectrolytes are found to reproduce main trends in experiments, whenever those results are available, and provide additional insight into the role played by the competitive adsorption of the counterions and polyelectrolytes on the surfaces.

S. K. Chun - One of the best experts on this subject based on the ideXlab platform.

  • Screening effects on the Degree of Ionization and hole mobility for p‐type Si and Ge
    Journal of Applied Physics, 1996
    Co-Authors: S. K. Chun
    Abstract:

    The Degree of Ionizations for Si and Ge with boron doping are calculated by taking into account the screening effect on the impurity energy level. The hole mobilities are then calculated as a function of doping concentration using the relaxation time approximation. Due to the screening effect on the impurity energy level, the Degree of Ionization increases over the entire temperature range. The ionized impurity scattering increases while the neutral impurity scattering decreases, and therefore the calculated mobilities for both Si and Ge agree well with the experimental data.

  • screening effects on the Degree of Ionization and hole mobility for p type si and ge
    Journal of Applied Physics, 1996
    Co-Authors: S. K. Chun
    Abstract:

    The Degree of Ionizations for Si and Ge with boron doping are calculated by taking into account the screening effect on the impurity energy level. The hole mobilities are then calculated as a function of doping concentration using the relaxation time approximation. Due to the screening effect on the impurity energy level, the Degree of Ionization increases over the entire temperature range. The ionized impurity scattering increases while the neutral impurity scattering decreases, and therefore the calculated mobilities for both Si and Ge agree well with the experimental data.

Masahiro Hasuo - One of the best experts on this subject based on the ideXlab platform.

  • On the Spatial Uniformity of the Degree of Ionization in a Helium ECR Plasma Produced under a Simple Cusp Field
    Atoms, 2019
    Co-Authors: Akira Ueda, Taiichi Shikama, Yohei Iida, Masahiro Hasuo
    Abstract:

    Production of a plasma that has a large Degree of Ionization (DOI), volume, and spatial and temporal uniformities is a challenge for the improvement of the performance of plasma-based vapor deposition processes. As a potential candidate for the discharge, we investigate plasma parameters arising in helium electron cyclotron resonance (ECR) discharges due to a simple cusp field. Two-dimensional distributions of helium atom emission-line intensities were measured using spectroscopy with multiple viewing chords and then de-convoluted by Abel inversion. The local plasma parameters, including the atomic density, were evaluated using collisional-radiative model analysis. The DOI calculated from the electron and atomic densities reached up to 35% and, in most of the region inside the ECR surface, it was more than 10%.

  • Spectroscopic measurement of the Degree of Ionization in a helium electron cyclotron resonance discharge in a simple cusp field
    Applied Physics Letters, 2017
    Co-Authors: Akira Ueda, Taiichi Shikama, Tatsuya Teramoto, Takanori Higashi, Yohei Iida, Masahiro Hasuo
    Abstract:

    For an electron cyclotron resonance (ECR) discharge, a simple cusp field can improve electron confinement and enhance the Degree of Ionization (DOI) without sacrificing accessibility to the plasma. In this study, the spatial distribution of the DOI is experimentally revealed in a helium plasma produced with widely used 2.45 GHz and 800 W microwaves. The DOI is evaluated from the electron density and ground state atom density measured using HeI emission line intensities and by collisional-radiative model analysis. It is found that the DOI increases to more than 15% within a reasonably large volume surrounded by the ECR surface and locally reaches as high as 25%.

Gama A Goicochea - One of the best experts on this subject based on the ideXlab platform.

  • dissipative particle dynamics simulations of weak polyelectrolyte adsorption on charged and neutral surfaces as a function of the Degree of Ionization
    Soft Matter, 2013
    Co-Authors: Francisco Alarcon, Elias Perez, Gama A Goicochea
    Abstract:

    The influence of the chain Degree of Ionization on the adsorption of weak polyelectrolytes on neutral and on oppositely and likely charged surfaces is investigated, by means of Monte Carlo simulations with a mesoscopic interaction model known as dissipative particle dynamics. The electrostatic interactions are calculated using the three-dimensional Ewald sum method, with an appropriate modification for confined systems. Effective wall forces confine the linear polyelectrolytes, and electric charges on the surfaces are included. The solvent, which is included explicitly, has a fluctuating particle number. The results show that the polyelectrolytes adsorb onto both neutral and charged surfaces, with the adsorption regulated by the chain Degree of Ionization, being larger at lower Ionization Degrees, where polyelectrolytes are less charged. Furthermore, polyelectrolyte adsorption is strongly modulated by the counterions screening of surface charges. These findings are supported by predictions of adsorption isotherms with varying Ionization Degrees. We obtain also the surface force mediated by adsorbed polyelectrolytes, which is calculated for the first time as a function of Ionization Degree. The adsorption and surface force isotherms obtained for weak polyelectrolytes are found to reproduce main trends in experiments, whenever those results are available, and provide additional insight into the role played by the competitive adsorption of the counterions and polyelectrolytes on the surfaces.

  • dissipative particle dynamics simulations of weak polyelectrolyte adsorption on charged and neutral surfaces as a function of the Degree of Ionization
    arXiv: Biological Physics, 2012
    Co-Authors: Francisco Alarcon, Elias Perez, Gama A Goicochea
    Abstract:

    The influence of the chain Degree of Ionization on the adsorption of weak polyelectrolytes on neutral and on oppositely and likely charged surfaces is investigated for the first time, by means of Monte Carlo simulations with the mesoscopic interaction model known as dissipative particle dynamics. The electrostatic interactions are calculated using the three-dimensional Ewald sum method, with an appropriate modification for confined systems. Effective wall forces confine the linear polyelectrolytes, and electric charges on the surfaces are included. The solvent is included explicitly also and it is modeled as an athermal solvent for the polyelectrolytes. The number of solvent particles is allowed to fluctuate. The results show that the polyelectrolytes adsorb both onto neutral and charged surfaces, with the adsorption regulated by the chain Degree of Ionization, being larger at lower Ionization Degrees, where polyelectrolytes are less charged. Furthermore, polyelectrolyte adsorption is strongly modulated by the counterions screening of surface charge. These findings are supported with predictions of adsorption isotherms with varying Ionization Degree. We obtain also the surface force mediated by adsorbed polyelectrolytes, which is calculated for the first time as a function of Ionization Degree. The adsorption and surface force isotherms obtained for weak polyelectrolytes are found to reproduce main trends in experiments, whenever those results are available, and provide additional insight into the role played by the competitive adsorption of the counterions and polyelectrolytes on the surfaces.

Elias Perez - One of the best experts on this subject based on the ideXlab platform.

  • dissipative particle dynamics simulations of weak polyelectrolyte adsorption on charged and neutral surfaces as a function of the Degree of Ionization
    Soft Matter, 2013
    Co-Authors: Francisco Alarcon, Elias Perez, Gama A Goicochea
    Abstract:

    The influence of the chain Degree of Ionization on the adsorption of weak polyelectrolytes on neutral and on oppositely and likely charged surfaces is investigated, by means of Monte Carlo simulations with a mesoscopic interaction model known as dissipative particle dynamics. The electrostatic interactions are calculated using the three-dimensional Ewald sum method, with an appropriate modification for confined systems. Effective wall forces confine the linear polyelectrolytes, and electric charges on the surfaces are included. The solvent, which is included explicitly, has a fluctuating particle number. The results show that the polyelectrolytes adsorb onto both neutral and charged surfaces, with the adsorption regulated by the chain Degree of Ionization, being larger at lower Ionization Degrees, where polyelectrolytes are less charged. Furthermore, polyelectrolyte adsorption is strongly modulated by the counterions screening of surface charges. These findings are supported by predictions of adsorption isotherms with varying Ionization Degrees. We obtain also the surface force mediated by adsorbed polyelectrolytes, which is calculated for the first time as a function of Ionization Degree. The adsorption and surface force isotherms obtained for weak polyelectrolytes are found to reproduce main trends in experiments, whenever those results are available, and provide additional insight into the role played by the competitive adsorption of the counterions and polyelectrolytes on the surfaces.

  • dissipative particle dynamics simulations of weak polyelectrolyte adsorption on charged and neutral surfaces as a function of the Degree of Ionization
    arXiv: Biological Physics, 2012
    Co-Authors: Francisco Alarcon, Elias Perez, Gama A Goicochea
    Abstract:

    The influence of the chain Degree of Ionization on the adsorption of weak polyelectrolytes on neutral and on oppositely and likely charged surfaces is investigated for the first time, by means of Monte Carlo simulations with the mesoscopic interaction model known as dissipative particle dynamics. The electrostatic interactions are calculated using the three-dimensional Ewald sum method, with an appropriate modification for confined systems. Effective wall forces confine the linear polyelectrolytes, and electric charges on the surfaces are included. The solvent is included explicitly also and it is modeled as an athermal solvent for the polyelectrolytes. The number of solvent particles is allowed to fluctuate. The results show that the polyelectrolytes adsorb both onto neutral and charged surfaces, with the adsorption regulated by the chain Degree of Ionization, being larger at lower Ionization Degrees, where polyelectrolytes are less charged. Furthermore, polyelectrolyte adsorption is strongly modulated by the counterions screening of surface charge. These findings are supported with predictions of adsorption isotherms with varying Ionization Degree. We obtain also the surface force mediated by adsorbed polyelectrolytes, which is calculated for the first time as a function of Ionization Degree. The adsorption and surface force isotherms obtained for weak polyelectrolytes are found to reproduce main trends in experiments, whenever those results are available, and provide additional insight into the role played by the competitive adsorption of the counterions and polyelectrolytes on the surfaces.