CHAD SOSOLIK - Academia.edu (original) (raw)
Papers by CHAD SOSOLIK
Cornell University - arXiv, Nov 14, 2018
Computer Physics Communications, Aug 1, 2022
Atoms
Direct detection of gravitational waves (GWs) on 17 August 2017, propagating from a binary neutro... more Direct detection of gravitational waves (GWs) on 17 August 2017, propagating from a binary neutron star merger, or a “kilonova”, opened the era of multimessenger astronomy. The ejected material from neutron star mergers, or “kilonova”, is a good candidate for optical and near infrared follow-up observations after the detection of GWs. The kilonova from the ejecta of GW1780817 provided the first evidence for the astrophysical site of the synthesis of heavy nuclei through the rapid neutron capture process or r-process. Since properties of the emission are largely affected by opacities of the ejected material, enhancements in the available r-process data is important for neutron star merger modeling. However, given the complexity of the electronic structure of these heavy elements, considerable efforts are still needed to converge to a reliable set of atomic structure data. The aim of this work is to alleviate this situation for low charge state elements in the Os-like isoelectronic se...
Surface Science
We present energy-and charge-resolved measurements of low and hyperthermal energy Na + ions scatt... more We present energy-and charge-resolved measurements of low and hyperthermal energy Na + ions scattered from a Ag(001) surface. With the primary ion beam oriented along the [110] crystal direction, distinct peaks in the energy distributions of the scattered beam flux that correspond to single or multiple collisions with target atoms are observed. A classical trajectory simulation reveals that these collisions can occur either at the surface or within the [110] channels, depending on incident beam energy. Within the simulation we probe the role of finite temperature and thermally displaced atoms on specific scattering events and show that contributions to the scattered distributions from single and double collisions dominate within the [110] channels. We also report velocity dependent measurements of the neutral/ion ratio of the scattered beam flux. A deviation between the data and simulated charge transfer results is observed for Na trajectories which penetrate the surface.
APS March Meeting Abstracts, Mar 1, 1998
We have measured trends in the trapping probability of O^+ and O_2^+ ions incident on Cu(001) for... more We have measured trends in the trapping probability of O^+ and O_2^+ ions incident on Cu(001) for incident energies below 400 eV for two incoming ion geometries: normal incidence and 45^circ incidence. These trends, which are relevant to ion-beam assisted and plasma thin film growth and surface processing, were measured using Auger Electron Spectroscopy. Absolute oxygen coverages were obtained by calibrating the Auger signal to the known saturation coverage of O on Cu(001). It has been shown previously for 5-600 eV Na^+ incident on Cu(001)( D.M. Goodstein et al., Phys. Rev. Lett. 78), 3213 (1997). that the energy dependent trend in the trapping probability varies strongly with the incident geometry. At normal incidence the trapping probability increases monotonically with decreasing energy. For 45^circ incidence, however, the trapping probability is non-monotonic, decreasing with energy to a minimum close to 20 eV, and then increasing again for energies below 20 eV. This behavior can be explained in terms of the trajectory types allowed by the effective surface corrugation experienced by the incident ion, which changes with the incident ion energy. Since Na and O are similar in size, their trapping behavior is expected to follow similar trends. Differences in these trends reflect differences in electronic structure and ion-surface potentials.
American Astronomical Society Meeting Abstracts #236, Jun 1, 2020
American Astronomical Society Meeting Abstracts #234, Jun 1, 2019
American Astronomical Society Meeting Abstracts #236, Jun 1, 2020
Bulletin of the American Physical Society, 2018
Bulletin of the American Physical Society, 2017
Bulletin of the American Astronomical Society, 2019
Bulletin of the American Physical Society, 2011
Bulletin of the American Physical Society, 2017
Bulletin of the American Physical Society, 2015
Bulletin of the American Astronomical Society, 2019
arXiv: High Energy Astrophysical Phenomena, 2019
Thanks to high-resolution and non-dispersive spectrometers onboard future X-ray missions such as ... more Thanks to high-resolution and non-dispersive spectrometers onboard future X-ray missions such as XRISM and Athena, we are finally poised to answer important questions about the formation and evolution of galaxies and large-scale structure. However, we currently lack an adequate understanding of many atomic processes behind the spectral features we will soon observe. Large error bars on parameters as critical as transition energies and atomic cross sections can lead to unacceptable uncertainties in the calculations of e.g., elemental abundance, velocity, and temperature. Unless we address these issues, we risk limiting the full scientific potential of these missions. Laboratory astrophysics, which comprises theoretical and experimental studies of the underlying physics behind observable astrophysical processes, is therefore central to the success of these missions.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2020
The ion-surface scattering simulation SAFARI was modified to accommodate non-rectilinear targets.... more The ion-surface scattering simulation SAFARI was modified to accommodate non-rectilinear targets. The basis for this change is discussed in the context of the computation time required for complex, nanostructured targets and the need to maintain the highly local molecular dynamics required for modeling low and hyperthermal energy ion trajectories. Results are presented for alkali ion scattering from noble metal targets (Au, Cu) and compared to experimental data. Scattering from a candidate nanostructured target, a stepped vicinal surface of Au, is also examined in detail and compared to an unstepped analogue to reveal step-dependent scattering features that could be measured in future experiments.
Cornell University - arXiv, Nov 14, 2018
Computer Physics Communications, Aug 1, 2022
Atoms
Direct detection of gravitational waves (GWs) on 17 August 2017, propagating from a binary neutro... more Direct detection of gravitational waves (GWs) on 17 August 2017, propagating from a binary neutron star merger, or a “kilonova”, opened the era of multimessenger astronomy. The ejected material from neutron star mergers, or “kilonova”, is a good candidate for optical and near infrared follow-up observations after the detection of GWs. The kilonova from the ejecta of GW1780817 provided the first evidence for the astrophysical site of the synthesis of heavy nuclei through the rapid neutron capture process or r-process. Since properties of the emission are largely affected by opacities of the ejected material, enhancements in the available r-process data is important for neutron star merger modeling. However, given the complexity of the electronic structure of these heavy elements, considerable efforts are still needed to converge to a reliable set of atomic structure data. The aim of this work is to alleviate this situation for low charge state elements in the Os-like isoelectronic se...
Surface Science
We present energy-and charge-resolved measurements of low and hyperthermal energy Na + ions scatt... more We present energy-and charge-resolved measurements of low and hyperthermal energy Na + ions scattered from a Ag(001) surface. With the primary ion beam oriented along the [110] crystal direction, distinct peaks in the energy distributions of the scattered beam flux that correspond to single or multiple collisions with target atoms are observed. A classical trajectory simulation reveals that these collisions can occur either at the surface or within the [110] channels, depending on incident beam energy. Within the simulation we probe the role of finite temperature and thermally displaced atoms on specific scattering events and show that contributions to the scattered distributions from single and double collisions dominate within the [110] channels. We also report velocity dependent measurements of the neutral/ion ratio of the scattered beam flux. A deviation between the data and simulated charge transfer results is observed for Na trajectories which penetrate the surface.
APS March Meeting Abstracts, Mar 1, 1998
We have measured trends in the trapping probability of O^+ and O_2^+ ions incident on Cu(001) for... more We have measured trends in the trapping probability of O^+ and O_2^+ ions incident on Cu(001) for incident energies below 400 eV for two incoming ion geometries: normal incidence and 45^circ incidence. These trends, which are relevant to ion-beam assisted and plasma thin film growth and surface processing, were measured using Auger Electron Spectroscopy. Absolute oxygen coverages were obtained by calibrating the Auger signal to the known saturation coverage of O on Cu(001). It has been shown previously for 5-600 eV Na^+ incident on Cu(001)( D.M. Goodstein et al., Phys. Rev. Lett. 78), 3213 (1997). that the energy dependent trend in the trapping probability varies strongly with the incident geometry. At normal incidence the trapping probability increases monotonically with decreasing energy. For 45^circ incidence, however, the trapping probability is non-monotonic, decreasing with energy to a minimum close to 20 eV, and then increasing again for energies below 20 eV. This behavior can be explained in terms of the trajectory types allowed by the effective surface corrugation experienced by the incident ion, which changes with the incident ion energy. Since Na and O are similar in size, their trapping behavior is expected to follow similar trends. Differences in these trends reflect differences in electronic structure and ion-surface potentials.
American Astronomical Society Meeting Abstracts #236, Jun 1, 2020
American Astronomical Society Meeting Abstracts #234, Jun 1, 2019
American Astronomical Society Meeting Abstracts #236, Jun 1, 2020
Bulletin of the American Physical Society, 2018
Bulletin of the American Physical Society, 2017
Bulletin of the American Astronomical Society, 2019
Bulletin of the American Physical Society, 2011
Bulletin of the American Physical Society, 2017
Bulletin of the American Physical Society, 2015
Bulletin of the American Astronomical Society, 2019
arXiv: High Energy Astrophysical Phenomena, 2019
Thanks to high-resolution and non-dispersive spectrometers onboard future X-ray missions such as ... more Thanks to high-resolution and non-dispersive spectrometers onboard future X-ray missions such as XRISM and Athena, we are finally poised to answer important questions about the formation and evolution of galaxies and large-scale structure. However, we currently lack an adequate understanding of many atomic processes behind the spectral features we will soon observe. Large error bars on parameters as critical as transition energies and atomic cross sections can lead to unacceptable uncertainties in the calculations of e.g., elemental abundance, velocity, and temperature. Unless we address these issues, we risk limiting the full scientific potential of these missions. Laboratory astrophysics, which comprises theoretical and experimental studies of the underlying physics behind observable astrophysical processes, is therefore central to the success of these missions.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2020
The ion-surface scattering simulation SAFARI was modified to accommodate non-rectilinear targets.... more The ion-surface scattering simulation SAFARI was modified to accommodate non-rectilinear targets. The basis for this change is discussed in the context of the computation time required for complex, nanostructured targets and the need to maintain the highly local molecular dynamics required for modeling low and hyperthermal energy ion trajectories. Results are presented for alkali ion scattering from noble metal targets (Au, Cu) and compared to experimental data. Scattering from a candidate nanostructured target, a stepped vicinal surface of Au, is also examined in detail and compared to an unstepped analogue to reveal step-dependent scattering features that could be measured in future experiments.