Page • Stochastic models are useful in chemical modeling at intermediate scales. Our work in this area includes the development of numerical methods for dealing with stiffness in the chemical Langevin equation and in kinetic Monte Carlo models. Stiffness in Stochastic Chemical Models We have developed time integration strategies that target efficient...
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Tandem Mass Spectrometry
Page • Although a powerful technique, analyzing molecules based on mass does not always enable us to identify specific molecular structures. Photoionization spectroscopy can yield isomer-specific information from mass spectrometry, but as the molecules grow larger in the chemistry leading to soot formation, for example, the photoionization spectra are no longer diagnostic....
Theoretical Chemistry
Page • Project/Program Description We use electronic structure methods, master equations, and molecular dynamics to explore and interpret transformations at the atomic scale in molecular systems. Impact Statement Figure 1 The potential energy surface of the acetylene + acetylene reaction. We are interested in chemical reactions and structural changes in molecules initiated...
Tim Zwier Awarded Miguel Catalán Medal
Post, September 17, 2025 • Tim Zwier, was awarded the Miguel Catalán Medal at the XVIII Iberian Joint Meeting on Atomic and Molecular Physics, July 21-24, 2025 in Vigo, Spain The medal, named for Prof. Miguel Catalán (1894-1957), honors a scientist for exceptional contributions and research record in the field of Atomic and Molecular Physics....
Timothy S. Zwier
Staff Page • Distinguished Member of Technical Staff, Gas Phase Chemical Physics Program, Combustion Research Facility. Biography Tim Zwier joined Sandia National Laboratories’ Combustion Research Facility (CRF) in January 2020 after spending much of his independent research career in academia. Zwier had served as PhD research advisor for more than 40 graduate students...
Transient Pulse-Response for Complex Systems
Post, May 6, 2026 • CRF researchers Nils Hansen, Emma Litzer, and David Osborn, together with colleagues Wenqi Zhou, Alexander R. Morey, Carey Chang and Coleman X. Kronawitter from UC Davis, published a paper on "Transient Pulse-Response Time-of-Flight Mass Spectrometry for Complex, Deactivating Heterogeneous Catalytic Systems: Application to Ethane Dehydroaromatization" in "The Journal of Physical...
Ultrafast Core-Level Spectroscopy
Page • Technical Details We investigate electronic excited state dynamics in gas phase molecules using ultrafast core-to-valence transient absorption spectroscopy. This technique combines element specificity with sensitivity to local bonding environment and spin state. In this experiment, an ultraviolet pump pulse electronically excites the molecule of interest, and an extreme ultraviolet (XUV)...
Ultrafast Infrared Spectroscopy
Page • Technical Details We investigate vibrational dynamics in electronic ground and excited states of gas phase and condensed phase systems using ultrafast infrared transient absorption spectroscopy. These experiments may utilize ultraviolet or narrowband infrared pump pulses to initiate the dynamics on an electronic excited or the electronic ground state of a...
Uncertainty Quantification
Page • Figure 1 Our work in uncertainty quantification (UQ) includes a range of research activities having to do with the quantification of uncertainty in computational model inputs and outputs. The work involves a focus on the development of numerical methods and open source software for statistical learning from data, forward propagation...
UQ Software
Page • Uncertainty Quantification Toolkit Overview The Uncertainty Quantification Toolkit (UQTk) is a lightweight open source C++ library, (available at http://www.sandia.gov/UQToolkit) primarily offering tools for the propagation of uncertain inputs and parameters through a computational model. Figure 1 UQTk allows other researchers to apply our algorithm UQ research to many other applications. It is well suited...
Visit
Page • We invite you to take a virtual tour of the CRF! Interested in visiting the Sandia California site in person? Visitors and potential collaborators are encouraged to explore the CRF’s research programs online before contacting the technical area manager to arrange a meeting. Click on image below for a more...
Vitalie Stavila
Staff Page • Principal Member of the Technical Staff. Visit my personal staff page here.
Watching molecules move
Post, September 29, 2017 • Velocity-Mapped Ion Imaging hits 30 years of research at SandiaBy Michael PadillaThirty years ago, David Chandler (8300) built an apparatus at Sandia’s Combustion Research Facility to image the fragments of a molecule as it fell apart. At the time, David had no idea what a tremendous impact his research would...
Wei Pan
Staff Page • Materials Physics. Biography Dr. Wei Pan is a Distinguished Member of the Technical Staff at Sandia National Laboratories. He obtained his Ph.D. degree in physics from Princeton University. He has made numerous seminal contributions to the field of many-particle physics in low dimensional electron systems (in particular novel fractional quantum...
Working with the CRF
Page • As an Office of Science collaborative research facility, a key aspect of the Combustion Research Facility’s mission is to encourage the direct involvement of individuals, or “collaborators,” from the scientific community. The CRF hosts many collaborators each year, who work side-by-side with staff researchers to develop new research methods and...
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