Accelerated Vibrational Energy Relaxation of Water in Alkaline Environments

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Publication date
DOI http://dx.doi.org/10.1021/acs.jpcb.1c02730
Reference R.O. Cota, S. Woutersen and H.J. Bakker, Accelerated Vibrational Energy Relaxation of Water in Alkaline Environments, J. Phys. Chem. B 125, 43: 11980-11986 (2021)
Group Ultrafast Spectroscopy

We observe that hydrated hydroxide ions introduce an additional relaxation channel for the vibrational relaxation of the OD vibrations of HDO molecules in aqueous NaOH solutions. This additional relaxation path involves resonant (Förster) vibrational energy transfer from the excited OD vibration to OH stretch vibrations of hydrated OH– complexes. This energy transfer constitutes an efficient mechanism for dissipation of the OD vibrational energy, as the accepting OH stretch vibrations show an extremely rapid subsequent relaxation with a time constant of <200 fs. We find that the Förster energy transfer is characterized by a Förster radius of 2.8 ± 0.2 Å.