Spighi Gloria, Gaveau Marc-André, Mestdagh Jean-Michel, Poisson Lionel, Soep Benoît
Laboratoire Francis Perrin, CNRS URA 2453, CEA, IRAMIS, Lidyl, Bat 522 F-91191 Gif/Yvette, France.
Phys Chem Chem Phys. 2014 May 28;16(20):9610-8. doi: 10.1039/c4cp00423j.
Benzophenone is a prototype molecule for photochemistry in the triplet state through its high triplet yield and reactivity. We have investigated its dynamics of triplet formation under the isolated gas phase conditions via femtosecond and nanosecond time resolved photoelectron spectroscopy. This represents the complete evolution from the excitation in S2 to the final decay of T1 to the ground state S0. We have found that the triplet formation can be described almost as a direct process in preparing T1, the lowest reacting triplet state, from the S1 state after S2 → S1 internal conversion. The molecule was also deposited by a pick-up technique on cold argon clusters providing a soft relaxation medium without evaporation of the molecule and the mechanism was identical. This cluster technique is a model for medium influenced electronic relaxation and provides a continuous transition from the isolated gas phase to the relaxation dynamics in solution.
二苯甲酮因其高三重态产率和反应活性，是三重态光化学的原型分子。我们通过飞秒和纳秒时间分辨光电子能谱，研究了其在孤立气相条件下三重态形成的动力学。这代表了从S2态激发到T1态最终衰减至基态S0的完整演化过程。我们发现，三重态形成几乎可以描述为一个直接过程，即在S2→S1内转换后，从S1态制备最低反应三重态T1。该分子还通过拾取技术沉积在冷氩团簇上，提供了一种无分子蒸发的软弛豫介质，且机制相同。这种团簇技术是介质影响电子弛豫的模型，提供了从孤立气相到溶液中弛豫动力学的连续转变。
