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Rotationally-Resolved Two-Dimensional Infrared Spectroscopy of CO2(g): Rotational Wavepackets and Angular Momentum
Kai C Gronborg1, Sydney M Giles1, Sean Garrett-Roe1
1Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania15260, United States.
The Journal of Physical Chemistry Letters
|August 25, 2022
Summary
We measured angular momentum transfer and wavepacket dynamics of carbon dioxide (CO2) using advanced 2D-IR spectroscopy. This study reveals insights into the rotational energy transfer of CO2 molecules at room temperature.
Area of Science:
- Physical Chemistry
- Molecular Spectroscopy
- Chemical Dynamics
Background:
- Understanding molecular dynamics, particularly angular momentum transfer, is crucial for predicting chemical reaction outcomes.
- Carbon dioxide (CO2) is a key molecule in atmospheric and industrial chemistry, making its dynamic properties of significant interest.
Purpose of the Study:
- To investigate the angular momentum transfer and wavepacket dynamics of CO2 molecules.
- To simultaneously observe the dynamics of multiple rotational levels in CO2.
Main Methods:
- Utilized polarization-resolved two-dimensional infrared (2D-IR) spectroscopy.
- Applied nonlinear response function theory to interpret the rotationally resolved 2D-IR spectra.
- Measured dynamics on the picosecond time scale at room temperature.
Main Results:
- Observed rotational wavepacket dynamics up to Jmax ≈ 50.
- Detected oscillations in peak intensities and beating patterns in 2D-IR spectra due to rotational wavepackets.
- Revealed information about angular momentum transfer through spectral diffusion analysis.
Conclusions:
- Demonstrated direct measurement of inelastic angular momentum dynamics across numerous rotational levels.
- Provided a comprehensive picosecond-scale understanding of CO2 rotational dynamics.
- Established 2D-IR spectroscopy as a powerful tool for probing angular momentum transfer in gases.
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