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Direct Imaging of Laser-driven Ultrafast Molecular Rotation
Published on: February 4, 2017
绘制分子运动的地图,以超明亮的电子导致电荷移位
Meng Gao1, Cheng Lu, Hubert Jean-Ruel
1Department of Chemistry and Physics, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
Nature
|April 20, 2013
概括
一个超明亮的秒电子源使得在相位过渡期间能够跟踪有机材料中的分子运动. 这一突破使得在微妙的化学和生物系统中研究超快速动态的原子分辨率.
科学领域:
- 材料科学 材料科学 材料科学
- 物理化学 物理化学
- 超快的动力学 超快的动力学
背景情况:
- 研究超快速过程需要将原子空间分辨率 (衍射) 与秒时间分辨率相结合.
- 有机材料由于散射弱,热可变性和热传导性差而带来挑战,需要极其明亮的源来获得高质量的数据.
- 现有的方法在激光诱导加热降解样品之前,难以捕捉结构动力学.
研究的目的:
- 为了证明超明亮的秒电子源对于研究有机材料中超快的结构动态的能力.
- 以原子分辨率研究有机盐 (EDO-TTF) 2PF6中光诱导的绝缘体到金属相变.
主要方法:
- 利用超明亮的秒电子源进行电子衍射.
- 采用 femtosecond 激光激发来触发相位过渡.
- 记录时间延迟的衍射模式,以绘制结构演变的地图.
- 执行了支持模型的计算.
主要成果:
- 在 (EDO-TTF) 2PF6.6中成功监测了光诱导绝缘体到金属相变期间的分子运动.
- 识别了数百个布拉格反射来绘制系统的结构演变.
- 观察到一个短暂的中间结构在五个皮秒内形成.
- 显著的分子运动驱动早期电荷移位,与参与后期金属状态转换的电荷移位.
结论:
- 超明亮的五秒电子源是探测不稳定有机系统中超快速结构动态的强大工具.
- 这项研究揭示了不同的分子运动,控制了绝缘体到金属相位过渡的不同阶段.
- 这种技术为在原子层面研究复杂的化学和生物过程开辟了新的途径.
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