Coherent Control of Radiationless Transitions

在这项由化学系实验物理化学计划资助的奖项中，戈登教授和他的学生将使用激光来控制电子激发的有机分子的驰豫速率。这种过程被称为“无辐射转变”，在视觉、诱变和致癌以及许多工业过程中起着至关重要的作用。例如，DNA的四个核苷酸组成块的一个独特属性是，它们将电子能量转换为振动能量的速度比碎裂快，从而使这些分子在紫外线照射下保持稳定。这种特性对于生命在地球表面的存在是必不可少的。该项目的目标是使用超短飞秒激光脉冲来加速或抑制这种无辐射跃迁的速度。通过理论和实验相结合的方法，对脉冲的时间分布进行优化，以达到预期的目的。这项研究符合化学反应相干控制的更大背景，在这种背景下，光脉冲被设计来控制化学和物理过程的结果。这项研究也将对这类重要的化学过程的机理提供更深入的理解。

In this award, funded by the Experimental Physical Chemistry Program of the Chemistry Division, Professor Gordon and his students will use lasers to control the relaxation rate of electronically excited organic molecules. Such processes, known as "radiationless transitions," play an essential role in vision, mutagenesis, and carcinogenesis, as well as in many industrial processes. For example, a unique property of the four nucleotide building blocks of DNA is that their conversion of electronic to vibrational energy is faster than fragmentation, allowing these molecules to be stable in the presence of ultraviolet radiation. This property is essential for life to exist on the surface of the earth. The goal of this project is to use ultrashort femtosecond laser pulses either to accelerate or inhibit the rate of such radiationless transitions. By using a combination of theory and experiment, the temporal profile of the pulses will be optimized to achieve the desired goal. This research fits into the larger context of coherent control of chemical reactions, in which light pulses are designed to control the outcome of chemical and physical processes. The research will also provide a deeper understanding of the mechanism of this important class of chemical processes.