Thomas Weinacht
Stony Brook University, NY·Physics
When a molecule absorbs light, its electrons and atomic nuclei start moving together in ways that cannot be separated. This coupled motion underlies vision, photosynthesis, solar cells, and the way DNA protects itself from ultraviolet damage.
- Fields
Physics
Chemistry
- Topics
ultrafast spectroscopy
attosecond science
femtosecond lasers
- Grants
- 1 known grant, through Aug 2027
What they work on
- Generate octave-spanning ultra-broadband laser pulses through self-phase modulation in stretched hollow-core fibers, so the pulses are short enough to follow electron and nuclear motion in real time.
- Shape these pulses in time with an acousto-optic, frequency-domain pulse shaper, which uses sound waves to adjust each color, so that pulse pairs are sensitive to detailed electron motion in small molecules.
- Measure the energy and direction of electrons and ions released when small molecules interact with pairs of shaped pulses, and use them to build movies of coupled electron-nuclear dynamics after light absorption.
- Compare these measurements of electronic coherence and entangled wave packets with approximate calculations, in order to develop improved models of how molecules behave after absorbing light.
More about the research
It is governed by quantum mechanics, so it is very hard to calculate. It is also very hard to watch, because it happens in about a femtosecond (10^-15 seconds) over distances of about an ångström (10^-10 meters).
Why it matters
A clearer picture of how molecules move after absorbing light could inform the design of better light-harvesting and energy-conversion technologies, such as solar cells. It also deepens the understanding of natural processes such as vision, photosynthesis, and DNA's protection against ultraviolet damage. Testing approximate theories against detailed measurements should help build more reliable models of these hard-to-calculate quantum dynamics.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Dmitri Romanov
Temple University, PA·Physics
Develop a predictive model of filament channel formation in dense gases, driven by inverse Bremsstrahlung, impact ionization and collisional excitation, and use it to explore control of the channels through pulse shape.
Benjamin Augenbraun
Williams College, MA·Physics
Measure the electronic, vibrational, rotational, and hyperfine (nuclear spin) structure of molecules pairing copper, silver, or gold with lead, using laser spectroscopy to see which wavelengths of light they absorb.
Paul Hess
Middlebury College, VT·Physics
Measure how strongly a single trapped ytterbium ion couples to a nearby bulk lead zirconate titanate piezoelectric resonator, detected as faster heating of the ion's motion on resonance.
The school
Stony Brook University: 32 labs on PI Pages, $319M a year on research, 289 research doctorates a year.
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