2011 Annual Report - Center for Integrated Nanotechnologies - Los ...

Theory & Simulation of Nanoscale Phenomena Thrust
Future Directions
In the coming year our efforts to understand nanoparticles in
complex environments will include extending calculations of the
forces between polymer-coated nanorods to systems in which
the polymer brush coating is different than the homopolymer matrix
as well as investigating the interactions of polymer brushes
with nanoparticles. This work will align with the Programmable
Membrane Based Nanocomposites IFA. We will also examine
longer chains of single strand DNA an attempt to reach the
neutral scaling regime. In order to further investigate the assembly
of particles, we will simulate the structure and mechanical
properties of dodecanethiol coated Au nanoparticle at the water/
vapor interface. We will extend studies of conjugated polymers
confined to optically active nanoparticles to ionizable carboxylate
and amine terminated side chains with varying degrees of
ionization, and we will model the effect of nanoparticles on the
mechanical strength of immiscible polymer films. In addition, we
will perform atomistic molecular dynamics simulations of a set of
poly(ethylene-co-acrylic acid) ionomers neutralized with various
cations to better understand nanoscale aggregation in these systems
and its effect on ion dynamics. In the theme of excitation
and transport, we will develop theory for a variety of integrated
nanosystems involving graphene including inelastic tunneling into
graphene with and without adsorbed nanostructures, novel electronic
states in quantum corrals on graphene, and the local electronic
signatures of a DNA base in a graphene nanopore. We
will extend the NA-ESMD package to be able to model excited
state dynamics within a Quantum Mechanics/Molecular Mechanics
(QM/MM) hybrid framework, and we will apply the NA-ESMD
package to model excited state dynamics in semiconductor
quantum dots. We will also apply the Exciton Scattering Model to
model energy transport and electron transfer in organic molecular
networks and apply previously developed TDDFT tools to
model the nonlinear optical response in semiconductor quantum
dots. We will also model nonlinear ultrafast optical pump-probe
response of correlated systems from first principles using model
Hamiltonians. Within the nanodomain/nanostructure interactions
science direction, we will add strain interactions to our models
of semiconductor surface reconstruction and further develop our
models of phase coexistence and competing orders at interfaces.
We will also develop the capability of modeling ultrafast optical
and terahertz spectroscopic probes of heterostructures, including
YBCO superconductors on ferromagnetic LSMO colossal magnetoresistance
films.
Postdoc Jason Haraldsen demonstrates the 3-D visualization capability at CINT
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38The Center for Integrated Nanotechnologies | 2011 Annual Report