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Updated: Jun 3, 2025

Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
Exploring the Vibrational Coherences in the Ultrafast Electronic Relaxation of Pyrimidine Nucleobases and Nucleosides
Shutaro Karashima1, Toshinori Suzuki1
1Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan.
Abstract:
We studied the vibrational coherences during the ultrafast internal conversions (ICs) of pyrimidine nucleobases and -sides in aqueous solutions and the gas phase with an instrumental resolution of 14 fs. The coherence of the same ring-breathing vibrational mode with a frequency of 750 cm-1 was observed. In the gas phase, the vibrational coherence was transferred during IC from the 1ππ* to the 1nπ* state, and it survived for approximately 1 ps. In an aqueous solution, the vibrational dynamics develop in the 1ππ* state because the 1nπ* state is energetically upshifted via hydrogen bonding with H2O, and the vibrational coherence is lost on a similar time scale as that of IC to the ground electronic state.
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