A5036381334- Energetic Materials and Combustion
- High-pressure geophysics and materials
- Machine Learning in Materials Science
- Polymer crystallization and properties
- Graphene research and applications
- High-Velocity Impact and Material Behavior
- Force Microscopy Techniques and Applications
- nanoparticles nucleation surface interactions
- Boron and Carbon Nanomaterials Research
- Material Dynamics and Properties
- Metal and Thin Film Mechanics
- Microstructure and mechanical properties
- Shape Memory Alloy Transformations
- Semiconductor materials and devices
- Thermal properties of materials
- Carbon Nanotubes in Composites
- 2D Materials and Applications
- Combustion and Detonation Processes
- Diamond and Carbon-based Materials Research
- Thermal and Kinetic Analysis
- Epoxy Resin Curing Processes
- Crystallography and molecular interactions
- Advanced Chemical Physics Studies
- Nanotechnology research and applications
- Glass properties and applications
Purdue University West Lafayette
2016-2025
Purdue University System
2017
Brookhaven National Laboratory
2012
Center for Functional Nanomaterials
2012
Los Alamos National Laboratory
2003-2007
California Institute of Technology
1999-2004
Fundación Ciencias Exactas y Naturales
1996-1999
University of Buenos Aires
1996-1999
To predict the structures, properties, and chemistry of materials involving silicon oxides; interfaces between these materials; hydrolysis such systems, we have developed ReaxFFSiO, reactive force field. The parameters for this field were obtained from fitting to results quantum chemical (QC) calculations on structures energy barriers a number oxide clusters equations state condensed phases Si SiO2 QC. We expect that ReaxFFSiO will allow accurate dynamical simulations bond breaking processes...
We extend the reactive force field ReaxFF to describe high energy nitramine RDX and use it with molecular dynamics (MD) study its shock-induced chemistry. studied shock propagation via nonequilibrium MD simulations at various collision velocities. find that for impact velocities ($>6\text{ }\text{ }\mathrm{k}\mathrm{m}/\mathrm{s}$) molecules decompose react form a variety of small in very short time scales ($<3\text{ }\mathrm{p}\mathrm{s}$). These products are consistent those found...
We use the recently developed reactive force field ReaxFF with molecular dynamics to study thermal induced chemistry in RDX [cyclic-[CH(2)N(NO(2))](3)] at various temperatures and densities. find that time evolution of potential energy can be described reasonably well a single exponential function from which we obtain an overall characteristic decomposition increases decreasing density shows Arrhenius temperature dependence. These timescales are reasonable quantitative agreement experimental...
Abstract Modeling and simulation is transforming modern materials science, becoming an important tool for the discovery of new material phenomena, gaining insight into processes that govern behavior, and, increasingly, quantitative predictions can be used as part a design in full partnership with experimental synthesis characterization. essential bridge from good science to engineering, spanning fundamental understanding behavior deliberate technologies leveraging properties processes. This...
The maximum superheating and undercooling achievable at various heating (or cooling) rates were investigated based on classical nucleation theory experiments, molecular dynamics (MD) simulations, dynamic experiments. highest lowest) temperature ${T}_{c}$ in a superheated solid an undercooled liquid) depends dimensionless barrier parameter $\ensuremath{\beta}$ the rate Q. material:...
Nonequilibrium melting and crystallization of a model Lennard-Jones system were investigated with molecular dynamics simulations to quantify the maximum superheating/supercooling at fixed pressure, over-pressurization/over-depressurization temperature. The temperature pressure hystereses found be equivalent regard Gibbs free energy barrier for nucleation liquid or solid. These results place upper bounds on hysteretic effects solidification in high heating- strain-rate experiments such as...
We use molecular dynamics simulations with the reactive potential ReaxFF to investigate initial reactions and subsequent decomposition in high-energy-density material α-HMX excited thermally via electric fields at various frequencies. focus on role of insult type strength energy increase for onset exothermic chemistry. find both these energies increasing rate input plateau as processes become athermal high loading rates. also that required and, a lesser extent, chemical depend type....
We use molecular dynamics simulations to describe the chemical reactions following shock-induced collapse of cylindrical pores in high-energy density material RDX. For shocks with particle velocities 2 km/s we find that a 40 nm diameter pore leads deflagration wave. Molecular collisions during lead ultrafast, multistep occur under nonequilibrium conditions. Exothermic products formed these first few picoseconds prevent nanoscale hotspot from quenching. Within 30 ps, local wave develops; it...
An efficient approach that combines short-term (minutes) high-energy dry ball milling and wet grinding to tailor the nano- microstructure of Ni+Al composite reactive particles is reported. Varying ball-milling conditions allows control volume fraction two distinct milling-induced microstructures, is, coarse nanolaminated. It found increasing nanolaminated structure present in leads a decrease their ignition temperature (Tig) from 700 500 K. Material with also be more sensitive impact when...
Abstract Reactive force fields have enabled an atomic level description of a wide range phenomena, from chemistry at extreme conditions to the operation electrochemical devices and catalysis. While significant insight semi-quantitative understanding been drawn such work, accuracy reactive limits quantitative predictions. We developed neural network field (NNRF) for CHNO systems describe decomposition reaction high-energy nitramine 1,3,5-trinitroperhydro-1,3,5-triazine (RDX). NNRF was trained...
The need for novel materials energy storage and generation calls chemical control at the atomic scale in nanomaterials. Ordered double-transition-metal MXenes expanded diversity of family atomically layered 2D since their discovery 2015. However, atomistic tunability ordered to achieve ideal composition-property relationships has not been yet possible. In this study, we demonstrate synthesis Mo2+αNb2-αAlC3 MAX phases (0 ≤ α 0.3) confirm preferential ordering behavior Mo Nb outer inner M...
We studied the thermal decomposition and subsequent reaction of energetic material nitromethane (CH(3)NO(2)) using molecular dynamics with ReaxFF, a first principles-based reactive force field. characterize chemistry liquid solid at high temperatures (2000-3000 K) density 1.97 g/cm(3) for times up to 200 ps. At T = 3000 K in is an intermolecular proton transfer leading CH(3)NOOH CH(2)NO(2). For lower (T 2500 2000 during often isomerization involving scission C-N bond formation C-O form...
We characterize the electronic structure and elasticity of monolayer transition-metal dichalcogenides MX2 (M=Mo, W, Sn, Hf X=S, Se, Te) with 2H 1T structures using fully relativistic first principles calculations based on density functional theory. focus role strain band alignment across series 2D materials. find that has a significant effect gap; biaxial 1% decreases gap in structures, by as much 0.2 eV MoS2 WS2, while increasing it for These results indicate is powerful avenue to modulate...
Successful doping of single-layer transition metal dichalcogenides (TMDs) remains a formidable barrier to their incorporation into range technologies. We use density functional theory study molybdenum and tungsten with large fraction the periodic table. An automated analysis energetics, atomic electronic structure thousands calculations results in insightful trends across table points out promising dopants be pursued experimentally. Beyond previously studied cases, our predictions suggest...
As the challenges in continued scaling of integrated circuit technology escalate every generation, there is an urgent need to find viable solutions for both front-end-of-line (transistors) and back-end-of-line (interconnects). For interconnect technology, it crucial replace conventional barrier liner with much thinner alternatives so that current driving capability interconnects can be maintained or even improved. Due inherent atomically thin body thicknesses, 2D materials have recently been...