About

Daniel M. Neumark is the Melvin Calvin Distinguished Professor of Chemistry at the University of California, Berkeley. Born in 1955, he holds a B.A. and M.A. from Harvard University (1977) and a Ph.D. in Physical Chemistry from UC Berkeley (1984). His research focuses on physical chemistry, molecular structure, and dynamics, with a particular emphasis on probing fundamental problems in chemical physics through state-of-the-art experiments. His laboratory projects include reaction dynamics of bimolecular and unimolecular reactions, cluster spectroscopy and dynamics, and ultrafast x-ray science, utilizing femtosecond and attosecond light sources to initiate and probe dynamics in the soft x-ray regime. Much of his work employs photoelectron spectroscopy of negative ions to investigate the spectroscopy and dynamics of transient and reactive species, leading to new insights into transition state spectroscopy, cluster electronic and vibrational spectroscopy, photodissociation of reactive radicals, hydrated electron dynamics, and ultrafast helium nanodroplet dynamics. Throughout his career, he has received numerous awards and honors, including election to the National Academy of Sciences, fellowships in major scientific societies, and recognition for his contributions to chemical physics and physical chemistry.

Research topics

• Physics
• Atomic physics
• Optics
• Molecular physics
• Materials science
• Physical chemistry
• Quantum mechanics
• Chemistry
• Nuclear magnetic resonance
• Optoelectronics
• Condensed matter physics
• Chromatography
• Organic chemistry
• Photochemistry
• Thermodynamics

Selected publications

• High-resolution Photoelectron Spectroscopy of Cryogenically Cooled VO 3 H 2 −

  ChemRxiv · 2026-02-24

  articleOpen accessSenior author

  High-resolution photoelectron spectra of cryogenically cooled VO3H2 − anions obtained with slow electron velocity-map imaging (cryo-SEVI) are reported. Comparison with DFT calculations shows that the spectra are from the cis-VO(OH)2 − dissociative adduct. The same complex is formed through either the VO2ˉ + H2O or VO3ˉ + H2 pathways, with the latter yielding significantly more ions. The experiment yields an electron affinity of 1.857(1) eV and several vibrational frequencies for the neutral species. Comparisons to Franck-Condon (FC) simulations show good agreement with the experimental features, but there are several transitions that do not appear in the simulations. These features are assigned to FC-forbidden transitions involving nontotally symmetric vibrational modes and are attributed to Herzberg-Teller (HT) coupling with the excited 𝐶𝐶 ̃1𝐵𝐵 2 anion state. The results are compared to the previous (cryo-SEVI) study of the titania water-split adduct, TiO3H2 − to explore the role of the additional vanadium valence electron in the spectroscopy and chemistry of these adducts.

  PublisherDOI

• Supplementary document for All-optical logic gates for extreme ultraviolet switching via attosecond four-wave mixing - 7745914.pdf

  Figshare · 2026-01-01

  articleOpen access

  This supplemental document contains further details concerning the FWM phase matching, the full Hamiltonians, the TDSE simulation parameters, and the impact of potential CEP fluctuations.

  PublisherDOI

• High-Resolution Photoelectron Spectroscopy of Cryogenically Cooled VO ₃ H ₂ ^–

  The Journal of Physical Chemistry A · 2026-04-06

  articleSenior authorCorresponding

  High-resolution photoelectron spectra of cryogenically cooled VO3H2– anions obtained with slow electron velocity-map imaging (cryo-SEVI) are reported. Comparison with DFT calculations shows that the spectra are from the cis-VO(OH)2– dissociative adduct. The same complex is formed through either the VO2– + H2O or VO3– + H2 pathways, with the latter yielding significantly more ions. The experiment yields an electron affinity of 1.857(1) eV and several vibrational frequencies for the neutral species. Comparisons to Franck–Condon (FC) simulations show good agreement with the experimental features, but there are several transitions that do not appear in the simulations. These features are assigned to FC-forbidden transitions involving nontotally symmetric vibrational modes and are attributed to Herzberg–Teller (HT) coupling with the excited C̃1B2 anion state. The results are compared to the previous (cryo-SEVI) study of the titania water-split adduct, TiO3H2– to explore the role of the additional vanadium valence electron in the spectroscopy and chemistry of these adducts.

  PublisherDOI

• Roadmap on Attosecond Science

  ArXiv.org · 2026-04-16

  articleOpen access

  Twenty-five years have passed since the first experimental demonstration of attosecond pulses, marking the advent of our ability to resolve and control electron motion in real time. What began as a technological breakthrough - generating the shortest flashes ever produced - has evolved into a powerful approach for probing and steering electronic dynamics in atoms, molecules, and solids. This roadmap, authored by leading experts in the field, surveys the recent rapid progress in the generation and characterization of attosecond pulses, emerging attosecond measurement and control techniques, and their expanding range of applications. It reviews current and future developments in attosecond light sources, including novel laser technologies, waveform synthesizers, new schemes for high-order harmonic generation, attosecond pulse generation at free-electron lasers, and structured light. Advances in attosecond measurement methodologies are also discussed, encompassing all-attosecond pump-probe spectroscopy, attosecond four-wave mixing, attosecond microscopy, spectroscopy with light transients, and attosecond interferometry. Furthermore, the roadmap addresses applications of attosecond spectroscopy to reveal electron dynamics in molecules and condensed matter systems from both theoretical and experimental perspectives, and highlights emerging directions at the interface with quantum optics and quantum entanglement. Overall, this work aims to serve as a comprehensive resource for navigating the evolving landscape of attosecond science.

  PublisherOA PDF

• Supplementary document for All-optical logic gates for extreme ultraviolet switching via attosecond four-wave mixing - 7745914.pdf

  Figshare · 2026-01-01

  articleOpen access

  This supplemental document contains further details concerning the FWM phase matching, the full Hamiltonians, the TDSE simulation parameters, and the impact of potential CEP fluctuations.

  PublisherDOI

• Roadmap on Attosecond Science

  arXiv (Cornell University) · 2026-04-16

  preprintOpen access

  Twenty-five years have passed since the first experimental demonstration of attosecond pulses, marking the advent of our ability to resolve and control electron motion in real time. What began as a technological breakthrough - generating the shortest flashes ever produced - has evolved into a powerful approach for probing and steering electronic dynamics in atoms, molecules, and solids. This roadmap, authored by leading experts in the field, surveys the recent rapid progress in the generation and characterization of attosecond pulses, emerging attosecond measurement and control techniques, and their expanding range of applications. It reviews current and future developments in attosecond light sources, including novel laser technologies, waveform synthesizers, new schemes for high-order harmonic generation, attosecond pulse generation at free-electron lasers, and structured light. Advances in attosecond measurement methodologies are also discussed, encompassing all-attosecond pump-probe spectroscopy, attosecond four-wave mixing, attosecond microscopy, spectroscopy with light transients, and attosecond interferometry. Furthermore, the roadmap addresses applications of attosecond spectroscopy to reveal electron dynamics in molecules and condensed matter systems from both theoretical and experimental perspectives, and highlights emerging directions at the interface with quantum optics and quantum entanglement. Overall, this work aims to serve as a comprehensive resource for navigating the evolving landscape of attosecond science.

  PublisherDOI

• Supplementary document for All-optical logic gates for extreme ultraviolet switching via attosecond four-wave mixing - 7745914.pdf

  Open MIND · 2026-01-01

  article

  This supplemental document contains further details concerning the FWM phase matching, the full Hamiltonians, the TDSE simulation parameters, and the impact of potential CEP fluctuations.

  DOI

• All-optical logic gates for extreme ultraviolet switching via attosecond four-wave mixing

  Optics Express · 2026-01-05 · 1 citations

  articleOpen access

  All-optical logic-gate-based switching is a prerequisite for photonic computing. This article introduces a logic-gate protocol for noncollinear four-wave mixing (FWM) of one attosecond extreme ultraviolet (XUV) with two few-femtosecond near infrared (NIR) pulses. Simulations show that the NIR carrier-envelope phases (CEPs) alter the spatial distribution of the XUV FWM emission, using doubly-excited states of gas-phase helium as an example. A complete set of logic gates-X(N)OR, (N)AND, and (N)OR-is realized for the 2s3p FWM signal at 63.66 eV with switching contrasts of 3.6 to 10.4. This theoretical study extends all-optical logic switching to the XUV and x-ray regimes and opens a new pathway for ultrafast photonic logic.

  PublisherDOI

• High-Resolution Photoelectron Spectroscopy of NO ₃ ^– Vibrationally Excited Along Its ν ₃ Mode

  The Journal of Physical Chemistry A · 2025-02-03 · 6 citations

  articleOpen accessSenior authorCorresponding

  The nitrate (NO3) radical has long been the subject of both experimental and theoretical studies due to its complex electronic structure resulting from vibronic interactions between its X̃2A2′ and B̃2E′ states. In particular, the definite assignment of the fundamental of its degenerate stretching vibration (ν3) is still under debate. Here, we report high-resolution photoelectron spectra of vibrationally pre-excited NO3– using the recently developed IR-cryo-SEVI technique. The anions are excited through infrared (IR) excitation near 1350 cm–1, accessing the ν3 and 2ν3(e′) vibrational levels with band centers at 1350.5 and ∼2700 cm–1, respectively. The IR-cryo-SEVI spectrum for 2ν3 pre-excitation shows clear evidence for an intense 321 transition. From the position of this feature (30031 cm–1), the electron affinity of NO3 also determined in this work (31680 cm–1), and the IR excitation energy, we obtain a fundamental frequency of 1051 cm–1 for the ν3 fundamental of the NO3 radical. This assignment and other features in the IR-cryo-SEVI spectra are supported by spectral simulations based on a vibronic Köppel–Domcke–Cederbaum Hamiltonian. The simulations also show that nearly all features in the IR-cryo-SEVI spectra arise because of pseudo-Jahn–Teller coupling between the X̃ and B̃ states of NO3. The results and analysis presented here settle a long-standing controversy regarding the ν3 frequency of NO3.

  PublisherOA PDFDOI

• Tracing Long-Lived Atomic Coherences Generated via Molecular Conical Intersections

  Physical Review Letters · 2025-10-16 · 1 citations

  articleOpen access

  Accessing coherences is key to fully understand and control ultrafast dynamics of complex quantum systems like molecules. Most photochemical processes are mediated by conical intersections, which generate coherences between electronic states in molecules. We show with accurate calculations performed on gas-phase methyl iodide that electronic coherences of spin-orbit-split states persist in atomic iodine after dissociation. Our simulation predicts a maximum magnitude of vibronic coherence in the molecular regime of 0.75% of the initially photoexcited state population. Upon dissociation, one-third of this coherence magnitude is transferred to a long-lived atomic coherence where vibrational decoherence can no longer occur. To trace these dynamics, we propose a tabletop experimental approach-heterodyned attosecond four-wave-mixing spectroscopy. This technique can temporally resolve small electronic coherence magnitudes and reconstruct the full complex coherence function via phase cycling. Hence, heterodyned attosecond four-wave-mixing spectroscopy leads the way to a complete understanding and optimal control of spin-orbit-coupled electronic states in photochemistry.

  PublisherDOI

Recent grants

• Spectroscopy, Dynamics, and Reactivity of Excess Electrons in Clusters

  NSF · $725k · 2007–2010

• Spectroscopy and Dynamics of Semiconductor, Metal, and Carbon Clusters using Photoelectron Imaging

  NSF · $450k · 2005–2008

• Dynamics in Anion Clusters and Liquid Jets Using Ultraviolet and Extreme-Ultraviolet Time-Resolved Photoelectron Spectroscopy

  NSF · $729k · 2017–2021

• Upgrade of Computational Facility for Research and Teaching

  NSF · $308k · 2009–2013

• Dynamics of Solvated Electrons in Clusters and Liquid Jets

  NSF · $712k · 2014–2017

Frequent coauthors

• Stephen R. Leone

  Lawrence Berkeley National Laboratory

  580 shared

• Knut R. Asmis

  Leipzig University

  146 shared

• Étienne Garand

  University of Wisconsin–Madison

  118 shared

• Mark Babin

  113 shared

• Oliver Geßner

  Lawrence Berkeley National Laboratory

  112 shared

• Jessalyn A. DeVine

  University of Göttingen

  102 shared

• Mark J. Abel

  Fritz Haber Institute of the Max Planck Society

  100 shared

• Marissa L. Weichman

  Princeton University

  93 shared

Awards & honors

• Office of Naval Research Young Investigator (1987)
• National Science Foundation Presidential Young Investigator…
• Alfred P. Sloan Fellow (1989)
• Camille and Henry Dreyfus Teacher-Scholar (1991)
• Fellow, American Physical Society (1993)