我々は、水中の溶媒和電子の過渡吸収に共鳴させたラマン散乱測定を行い、水の変角振動領域に新たな過渡共鳴ラマンバンドが観測されることを見出している。今回、ラマンバンドと溶媒和電子の吸収の時間挙動が一致することを確認し、観測されたラマンバンドが電子に溶媒和した水分子の振動に帰属されることを明らかにした。また、共鳴効果によるバンド強度増大の割合を定量的に見積もり、その機構を考察した。OH伸縮振動領域の共鳴ラマン測定の結果をあわせ、溶媒和電子周辺の局所溶媒和構造の共鳴ラマン効果について総括的に議論する。

We have found that a novel transient Raman band appears in the frequency region of the OH-bend mode of water when Raman spectra are measured under the condition resonant with the electronic transition of the solvated electron. We measured the temporal behavior of the transient Raman band, and confirmed that it agrees very well with the decay of the transient absorption due to the solvated electron. It implies that the observed Raman band is certainly ascribed to the vibration of the water molecules that solvate the electron. We estimated the factor of the resonance enhancement quantitatively and considered the resonance mechanism. In the presentation, we discuss this novel resonance Raman effect arising from the local solvation structure around the electron based on the Raman data that also include the data for the OH-stretch region.