Research

Ultrafast Chemistry

Radiation damage, mass spectrometry, and EUV photolithography are governed by electron-driven ion chemistry, but the decisive steps occur on femtosecond timescales and are usually inferred from final products rather than observed directly. We address this by measuring electron-impact and electron-induced reactions in real time and identifying nonstatistical mechanisms, including bond rearrangements and roaming that can precede energy redistribution. The central challenge is to extract mechanisms and timescales across up to 100 competing product channels and connect them to the underlying electronic structure.

Many chemically important processes, from aerosol and interfacial chemistry to plasma and radiation chemistry, occur in locally structured environments where a few neighboring molecules can radically change charge transfer, proton transfer, and fragmentation pathways. The problem is that we lack a molecular-level picture of how microsolvation and local geometry control the earliest branching between reaction and dissociation. We tackle this by using weakly bound molecular clusters as controllable reaction complexes that bridge isolated molecules and condensed-phase environments. Site-selective ionization launches a radical cation toward a neighboring molecule with tunable kinetic energy, allowing us to track charge transfer, proton transfer, and bond rearrangement on femtosecond timescales and identify when the dynamics becomes nonstatistical.

Strong-field ionization initiates much of the chemistry and damage driven by intense lasers, yet in polyatomic molecules the dominant pathways and energy-deposition mechanisms remain poorly quantified, limiting prediction and control of fragmentation. The problem is that multiphoton ionization, tunneling, and electron recollision can produce similar end products while depositing very different internal energies and electronic-state populations. We address this by disentangling these pathways and developing strategies to steer them, linking the ionization step to energy deposition and the resulting fragmentation. The outcome is a predictive framework that shows when common simplifying models fail and what variables truly control outcomes, enabling femtosecond-scale control before energy redistribution or collisions intervene.

Across ultrafast science, progress is increasingly limited by how precisely we can measure and control spectral phase and pulse structure under realistic, high-power experimental conditions. The problem is that small phase errors and pulse distortions can obscure mechanisms, reduce control, and prevent access to the shortest timescales and highest contrasts needed for modern coincidence and imaging measurements. We address this by developing precision phase metrology and adaptive pulse shaping that deliver shorter, cleaner, and more controllable femtosecond pulses, including methods compatible with high-power operation. These capabilities enable sub-5 fs, high-contrast excitation at peak intensities up to 10^18 W/cm2, strengthen the strong-field and reaction-dynamics programs above, and open opportunities in microscopy, next-generation photonics, optical computing, and sensing.

 

Contact / Webpage

Area(s) of Interest

Physical (Ph)

Analytical (An)

Biological (Bi)

Chemical Physics (CP)

Selected Publications

J. Stamm, S. S. Priyadarsini, S. Sandhu, A. Chakraborty, J. Shen, S. Kwon, J. Sandhu, C. Wicka, A. Mehmood, B. G. Levine, P. Piecuch, M. Dantus, “Factors governing H3+ formation from methyl halogens and pseudohalogens,” Nature Communications 16, 410 (2025). DOI: 10.1038/s41467-024-55065-5

M. Dantus, “Ultrafast studies of elusive chemical reactions in the gas phase,” Science 385, eadk1833 (2024). DOI: 10.1126/science.adk1833

J, Stamm, S. Kwon, S. Sandhu, J. Sandhu, B. Levine, M. Dantus, “Coherence mapping to identify the intermediates of multi-channel dissociative ionization,” Communications Chemistry 7, 103 (2024). DOI: 10.1038/s42004-024-01176-5

E. Prieto Zamudio, R. Das, N. Krishnakanth Katturi, J. Stamm, J. Sandhu, S. Kwon, M. Minasian, M. Dantus, “Enhanced strong-field ionization and fragmentation of methanol using non-commensurate field,” J. Phys. Chem. A 128, 9099 (2024). DOI: 10.1021/acs.jpca.4c05584

M. Dantus, “Tracking Molecular Fragmentation in Electron-Ionization Mass Spectrometry with Ultrafast Time Resolution,” Accounts of Chemical Research 57, 033003 (2024). DOI: 10.1021/acs.accounts.3c00713

CV

• 2024– Professor, Department of Electrical and Computer Engineering, Michigan State University
• 2015– MSU Foundation Professor, Michigan State University
• 2015– University Distinguished Professor, Michigan State University
• 2002– Professor, Department of Chemistry, Michigan State University
• 2001– Adjunct Professor, Department of Physics and Astronomy, Michigan State University
• 1999–2002 Associate Professor, Department of Chemistry, Michigan State University
• 1993–1999 Assistant Professor, Department of Chemistry, Michigan State University
• 1991–1993 Postdoctoral Research Fellow, California Institute of Technology
• 1985–1993 PhD in Chemical Physics, California Institute of Technology

Awards

Year	Award	Organization
2023	Ahmed Zewail Award in Ultrafast Science and Technology	ACS
2020	Modern Optics and Spectroscopy Seminar	MIT
2019	Richard B. Bernstein Lecture	University of California, Los Angeles
2019	Technology Transfer Award	Michigan State University
2015	MSU Foundation Chair	Michigan State University
2015	University Distinguished Professor	Michigan State University
2014	Fellow	Optical Society of America (Optica)
2014	Fellow	American Physical Society
2014	Fellow	National Academy of Inventors
2013	Inventor of the Year Award	Michigan State University
2022	CLEO/Laser Focus World Innovation Award Winner (development of femtoAdaptiv)
2009	PhAST/Laser Focus World Innovation Award Winner (development of femtoFit)
2008	University Distinguished Faculty Award,	Michigan State University
2007	Laser Focus World Commendation for Excellence in Technical Communications
2007	PhAST/Laser Focus World Innovation Award Honorable Mention (development of MIIPS)
2006	College of Natural Sciences Distinguished Faculty Award	Michigan State University
2001	Plenary Speaker, 8th International Workshop on Femtosecond Technology	Tsukuba, Japan
2001	Featured in ACS 125th Anniversary Issue of Chemical & Engineering News
1998	Camille Dreyfus Teacher-Scholar Award
1998	Alred P. Sloan Research Fellow
1996	Lilly Teaching Fellowship
1995	Packard Fellowship for Science and Engineering	The David and Lucile Packard Foundation
1995	Beckman Young Investigator Award	Beckman Foundation
1994	General Electric Foundation Faculty Award	General Electric
1993	New Faculty Award	Camille and Henry Dreyfus Foundation
1992	Nobel Laureate Signature award for Graduate Education in Chemistry	American Chemical Society
1991	Milton and Francis Clauser Doctoral Prize	California Institute of Technology
1991	Camille and Henry Dreyfus New Faculty Award
1991	Milton and Francis Clauser Doctoral Prize	California Institute of Technology
1991	Herbert Newby McCoy Award	California Institute of Technology
1985	Phi Beta Kappa	Brandeis University, Waltham, MA