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Home  /  Faculty  /  Mitchio Okumura

Mitchio Okumura

Research Summary
Laser Spectroscopy, Kinetics and Reaction Dynamics; Atmospheric Chemistry
Profile

Assistant: Elisha Jung Okawa

The Okumura Group is interested in the application of laser spectroscopy and reaction dynamics to problems in atmospheric chemistry and climate change. We study atmospheric free radicals and transient intermediates in order to understand the reactions and photochemistry that are most important in the troposphere and stratosphere, as well as in planetary atmospheres such as those of Mars and Titan. Our goal is both to determine parameters of key reactions and species in the atmosphere, and to understand the chemical physics of these processes at the most fundamental level. To achieve high sensitivities required for these experiments, we develop and apply state-of-the-art methods such as cavity-enhanced spectroscopy, frequency comb lasers, and VUV mass spectrometry using synchrotron radiation. We also apply high resolution spectroscopy for measuring spectroscopic parameters needed for the latest generation of CO2 satellites. Our group has extensive collaborations with scientists at the NASA Jet Propulsion Laboratory.

  • Laser spectroscopy of reactive intermediates
  • Development of methods in cavity-enhanced, cavity-ringdown and frequency comb laser spectroscopy
  • Reaction rates, mechanisms and dynamics of free radicals, clusters, and transient species
  • Chemistry of peroxyl and alkoxyl radicals
  • Photochemistry and photodissociation dynamics
  • Nonadiabatic effects and multiple surfaces in radical reactions
  • Kinetic isotope effects; clumped isotopes
  • High precision spectroscopy with applications in remote sensing of greenhouse gases such as NASA's Orbiting Carbon Observatory (OCO-2) mission


Publications

For a complete publications list, see feeds.library.caltech.edu
2025-26
Ch 125 abc. The Elements of Quantum Chemistry. 9 units (3-0-6); first, second, third terms, 2025-26. Prerequisites: Ch 21 abc or an equivalent brief introduction to quantum mechanics. A treatment of quantum mechanics with application to molecular and material systems. The basic elements of quantum mechanics, the electronic structure of atoms and molecules, the interactions of radiation fields and matter, and time dependent techniques relevant to spectroscopy will be covered. The course sequence prepares students for Ch 126, Ch 225, and 226.
Instructors: Cushing (a), Weitekamp (b), Okumura (c)
Ch 135. Chemical Kinetics and Reaction Dynamics. 9 units (3-0-6); second term, 2025-26. Prerequisites: Ch 21 abc and Ch 41 abc, and Ch 125 a or equivalent, or instructor's permission. Physical description and computations of chemical reactions and photochemistry with applications in air pollution, planetary atmospheres and condensed phases. Topics include: kinetic modeling, time-dependent quantum mechanics, rate constants, transition state theory intermolecular potentials, classical two-body elastic scattering, reactive scattering, nonadiabatic processes, statistical theories of unimolecular reactions, photochemistry, laser and molecular beam methods, theory of electron transfer, solvent effects, condensed phase dynamics, surface reactions, isotope effects.
Instructor: Okumura
Ch 252. Advanced Topics in Chemical Physics. Hours and units to be arranged; first term, 2025-26. Content will vary from year to year; topics are chosen according to the interests of students and staff.
Instructor: Okumura
Ch 6 ab. Physical and Biophysical Chemistry Laboratory. 9 units (1-5-3); first term, 2025-26. Prerequisites: Ch 1, Ch 4 a, and Ch 21 or equivalents (may be taken concurrently). Introduction to modern physical methods in chemistry and biology. Techniques include laser spectroscopy, microwave spectroscopy, electron spin resonance, nuclear magnetic resonance, mass spectrometry, FT-IR, fluorescence, scanning probe microscopies, and UHV surface methods.
Instructor: Okumura
2022-23
Ch 135. Spectroscopy and Dynamics of Molecules. 9 units (3-0-6); second term, 2022-23. Prerequisites: Ch 21 abc and Ch 41 abc, and Ch 125 a or equivalent, or instructor's permission. Physical description of the structure, spectra and dynamics of molecules. Topics include: time-dependent quantum mechanics, molecular structure, coherence, path integral formalism, scattering cross sections, rate constants, intermolecular potentials, classical two-body elastic scattering, reactive scattering, nonadiabatic processes, statistical theories of unimolecular reactions, photochemistry, laser and molecular beam methods, theory of electron transfer, solvent effects, condensed phase dynamics, surface reactions, isotope effects.
Instructor: Okumura