skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Pseudo-atom Molecular Dynamics in Pictures

Abstract

This report is a presentation given during the High-T EOS meeting at LANL. It describes existing tools and models used to analyze quantum dynamics.

Authors:
 [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1321710
Report Number(s):
LA-UR-16-26745
DOE Contract Number:
AC52-06NA25396
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats

Starrett, Charles Edward. Pseudo-atom Molecular Dynamics in Pictures. United States: N. p., 2016. Web. doi:10.2172/1321710.
Starrett, Charles Edward. Pseudo-atom Molecular Dynamics in Pictures. United States. doi:10.2172/1321710.
Starrett, Charles Edward. 2016. "Pseudo-atom Molecular Dynamics in Pictures". United States. doi:10.2172/1321710. https://www.osti.gov/servlets/purl/1321710.
@article{osti_1321710,
title = {Pseudo-atom Molecular Dynamics in Pictures},
author = {Starrett, Charles Edward},
abstractNote = {This report is a presentation given during the High-T EOS meeting at LANL. It describes existing tools and models used to analyze quantum dynamics.},
doi = {10.2172/1321710},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2016,
month = 9
}

Technical Report:

Save / Share:
  • This program performs atomic scale computer simulations of the structure and dynamics of metallic system using energetices based on the Embedded Atom Method. The program performs two types of calculations. First, it performs local energy minimization of all atomic positions to determine ground state and saddle point energies and structures. Second, it performs molecular dynamics simulations to determine thermodynamics or miscroscopic dynamics of the system. In both cases, various constraints can be applied to the system. The volume of the system can be varied automatically to achieve any desired external pressure. The temperature in molecular dynamics simulations can be controlledmore » by a variety of methods. Further, the temperature control can be applied either to the entire system or just a subset of the atoms that would act as a thermal source/sink. The motion of one or more of the atoms can be constrained to either simulate the effects of bulk boundary conditions or to facilitate the determination of saddle point configurations. The simulations are performed with periodic boundary conditions.« less
  • Organometal halide perovskites are attracting great attention as promising material for solar cells because of their high power conversion efficiency. The high performance has been attributed to the existence of free charge carriers and their large diffusion lengths, but the nature of carrier transport at the atomistic level remains elusive. Here, nonadiabatic quantum molecular dynamics simulations elucidate the mechanisms underlying the excellent free-carrier transport in CH 3NH 3PbI 3. Pb and I sublattices act as disjunct pathways for rapid and balanced transport of photoexcited electrons and holes, respectively, while minimizing efficiency-degrading charge recombination. On the other hand, CH 3NH 3more » sublattice quickly screens out electrostatic electron-hole attraction to generate free carriers within 1 ps. Together this nano-architecture lets photoexcited electrons and holes dissociate instantaneously and travel far away to be harvested before dissipated as heat. As a result, this work provides much needed structure-property relationships and time-resolved information that potentially lead to rational design of efficient solar cells.« less
  • Damage to DNA, Inhibition of DNA replication and mitosis, appearance of abnormal keratin peptide and large differentiated cells and, finally, death of cells occur dose- and time-responsively in submerged cultures of keratinocytes exposed to bis-(b-chloroethyl)sulfide (BCES). However, the relevance of these parameters to vesication in human skin exposed to mustard in vivo has yet to be established. The pseudo-epidermis cultured from human cutaneous keratinocytes offers a system in which the pathogenic importance of each of these parameters can be evaluated. To establish the validity of the system, it is necessary to show that the pseudo-epidermis undergoes similar dose- and time-dependentmore » cytotoxicity from BCES as is observed in the human skin after topical exposure to the mustard. This report includes data which demonstrate a dose- and time-dependent destruction of the germinative layer in human pseudo-epidermis after topical application of BCES. In addition, data are included to show that DNA is a primary target for BCES in pseudo-epidermis as it is in vivo. Also included in this report is a proposed sequence of molecular and cellular events to account for cytotoxicity in the germinative population of the pseudo-epidermis after exposure to BCES.« less