Materials and Chemistry Theory@ORNL
Oak Ridge National Laboratory in cooperation with the U.S. Department
of Energy conducts a broad range of theoretical research in materials
sciences and chemistry. This work is tightly integrated with experimental
programs and involves development and application of advanced theoretical
methods and utilizes some of the world's fastest computers to solve some
of the most pressing energy challenges facing our nation.
Techniques employed include first principles methods based on density
functional theory, quantum chemistry, classical and
ab initio molecular dynamics, transport theory, many body theory,
quantum Monte Carlo, phase field analysis and statistical mechanics.
Solutions to the pressing energy challenges that ORNL undertakes
often require a combination of two or more theoretical approaches in
conjunction with with experimental work. Many of these
techniques are broadly applicable across wide ranges of chemistry
and materials. As such, theory at ORNL often plays a cross-cutting
role, with ORNL theorists bridging different areas of energy
What is Theory:
Theory is about understanding, prediction, exploration
of new conditions before they are realized in the laboratory and
drawing connections between experimental observations. Theory at ORNL
impacts our programs through prediction of new phenomena, interpretations
of experimental results, and by providing novel directions for discovering
new materials and chemical systems.
ORNL has a full range of theory activities. These
range from basic energy science
aimed at laying the ground-work for long term solutions to our
energy problems to near term work addressing our nation's most
pressing energy and security needs.
Cray X1 supercomputer installed at ORNL. ORNL and
the National Center for Computational Sciences are consistently is among the
top open research computer centers world wide in terms of capacity.
Capabilities and Infrastructure:
ORNL scientists apply a wide range of methods ranging from analytic
methods to simulations on the world's fastest computers. These include
numerical solution of quantum many body models, first principles calculations
with chemical specificity, and continuum modeling.
Often solutions to challenging problems are found only by combinations
The laboratory has strong computational capabilities, including group level
computers and clusters, midrange institutional clusters with hundreds of
processors, and some of the world's fastest supercomputers.
We benefit from codes and algorithms developed at ORNL by the Office
of Advanced Scientific Computing Research.
Fermi surface of LaFeAsO, parent of the iron based high temperature
superconductors, as obtained within density functional theory.
Superconductors may allow low loss
electricity distribution, a more reliable electric grid and more efficient
motors and generators.
Fundamental Energy Research:
ORNL carries out a broad range of fundamental research aimed at expanding
the scientific foundations for new, better and more environmentally
friendly energy technologies. New characterization tools
such as the Spallation Neutron Source and advanced imaging methods
are allowing researchers to explore matter at previously unthinkable
scales. Theory plays a key role in these efforts by providing
understanding of observations, predictions to be tested by experiment
and by suggesting novel experiments.
Theory and Materials Discovery:
One of the most pressing needs for energy technology is the
discovery of new advanced materials. Traditionally, this involved
exploring compositions guided by chemical intuition, experience
and general principles. Nowadays, first principles calculations
can greatly accelerate this process by providing atomic level
understanding of phenomena and predictions of chemical trends.
The ORNL program makes extensive use of these methods in conjunction
Nanomaterials and new phenomena that only exist at the nanoscale
offer the potential for solving some of the most demanding energy problems
Developing these technologies will require answering scientific questions
such as: How do we predict the properties of nanostructured Materials?
What nanostructures will display different and useful properties?
How do we synthesize desired nanomaterials?
As such, theory plays a particularly
important role in nanoscience.
Applications at ORNL include designing nanostructures for novel
sensors, hydrogen storage and nanoscale electronic devices.
As a sector, transportation provides our nation's greatest opportunities
for energy savings. Achieving these savings while maintaining the quality,
safety and convenience afforded by current technologies requires
high technology gee-whiz advances that are at the same time cost-effective
and amenable to large scale manufacturing. At ORNL theory is integrated
into experimental programs seeking new advanced materials and processes
for engine components, waste heat recovery, catalysts, advanced batteries
and the storage and utilization of hydrogen fuel. Recent accomplishments
include the prediction of low cost thermoelectric materials for waste
heat recovery as well as new materials for hydrogen storage.
ORNL has a long history of innovation in structural materials,
including high temperature superalloys that have revolutionized
turbine design, dispersion hardened steels, structural ceramics
and light-weight materials for transportation applications.
Theory plays an important role in the ORNL effort. Examples include
studies of dislocations, anti-phase boundaries, stacking faults
and failure mechanisms in intermetallic compounds and alloys, and
first principles investigation of the structure and chemistry of intergrain
regions in ceramics. Theory is also being used to provide atomic
scale microscopic understanding of the mechanisms of hydrogen embrittlement.
Energetics and structure of the amphoteric O-H complex in CdTe. This
complex was found to be important in obtaining carrier compensation essential
for (Cd,Zn)Te based spectroscopic radiation detection. This capability is
needed in homeland security and nuclear non-proliferation missions.
Understanding and controlling the behavior of materials under extreme
conditions, such as high temperature and high radiation flux will be
important in future energy technologies, such as next generation
nuclear reactors and fusion reactors. Theory plays a crucial role
in these activities because of the difficulty and long times needed
for experimental studies.
Dynamical simulations of radiation events and healing of radiation damage
in structural materials under various conditions have yielded
important insights into the mechanisms of radiation damage and ways
of mitigating them.
National Security and Non-Proliferation:
Theory and modeling at ORNL are used to support the development of
novel chemical and biological sensors for national security and homeland
defense applications. This includes the design of nanoscale sensors in
areas such as explosive detection.
The laboratory maintains a substantial theory effort integrated with
experimental activities in the ORNL Center for Radiation Detection
Materials and Systems. This effort uses first principles and other
approaches in finding ways to improve materials for spectroscopic
gamma ray detection and neutron detection and imaging for nuclear
non-proliferation and other applications.
For further information:
M.V. Buchanan, Associate Laboratory Director,
Images courtesy of P.R.C. Kent, R.E. Stoller, M.H. Du and D.J. Singh.