1. Femtosecond symmetry breaking and coherent relaxation of methane cations via x-ray spectroscopy.
- Author
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Ridente, Enrico, Hait, Diptarka, Haugen, Eric A., Ross, Andrew D., Neumark, Daniel M., Head-Gordon, Martin, and Leone, Stephen R.
- Subjects
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X-ray spectroscopy , *MOLECULAR relaxation , *METHANE , *SOFT X rays , *MOLECULAR dynamics , *SYMMETRY breaking , *X-ray absorption - Abstract
Understanding the relaxation pathways of photoexcited molecules is essential to gain atomistic-level insight into photochemistry. We performed a time-resolved study of ultrafast molecular symmetry breaking through geometric relaxation (Jahn-Teller distortion) on the methane cation. Attosecond transient absorption spectroscopy with soft x-rays at the carbon K-edge revealed that the distortion occurred within 10 ± 2 femtoseconds after few-femtosecond strong-field ionization of methane. The distortion activated coherent oscillations in the asymmetric scissoring vibrational mode of the symmetry-broken cation, which were detected in the x-ray signal. These oscillations were damped within 58 ± 13 femtoseconds because vibrational coherence was lost with the energy redistributing into lower-frequency vibrational modes. This study completely reconstructs the molecular relaxation dynamics of this prototypical example and opens avenues for exploring complex systems. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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