Magnetic recording using femtosecond laser pulses has recently been achieved in some dielectric media, showing potential for ultrafast data storage applications. Single-molecule magnets (SMMs) are metal complexes with two degenerate magnetic ground states and are promising for increasing storage density, but remain unexplored using ultrafast techniques. Here we have explored the dynamics occurring after photoexcitation of a trinuclear µ3-oxo-bridged Mn(III)-based SMM, whose magnetic anisotropy is closely related to the Jahn-Teller distortion. Ultrafast transient absorption spectroscopy in solution reveals oscillations superimposed on the decay traces due to a vibrational wavepacket. Based on complementary measurements and calculations on the monomer Mn(acac)3, we conclude that the wavepacket motion in the trinuclear SMM is constrained along the Jahn-Teller axis due to the µ3-oxo and µ-oxime bridges. Our results provide new possibilities for optical control of the magnetization in SMMs on femtosecond timescales and open up new molecular-design challenges to control the wavepacket motion in the excited state of polynuclear transition-metal complexes.

中文翻译：

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超快光激发后锰单分子磁体的振动相干性。

最近在某些介电介质中使用飞秒激光脉冲进行磁记录，显示出超快数据存储应用的潜力。单分子磁体（SMM）是具有两个简并磁性基态的金属络合物，有望提高存储密度，但仍未使用超快技术进行探索。在这里，我们研究了光激发三核μ3-氧桥联的Mn（III）基SMM后发生的动力学，该SMM的磁各向异性与Jahn-Teller变形密切相关。溶液中的超快速瞬态吸收光谱法揭示了由于振动波包而叠加在衰减迹线上的振荡。根据对单体Mn（acac）3的补充测量和计算，我们得出的结论是，由于µ3-oxo和µ-oxime桥，三核SMM中的波包运动沿Jahn-Teller轴受到约束。我们的研究结果为飞秒时间尺度上的SMM磁化的光学控制提供了新的可能性，并提出了新的分子设计挑战，以控制多核过渡金属配合物在激发态下的波包运动。