Spectroscopy and dynamics of molecules at very low temperatures

在超冷原子研究取得成功的鼓舞下，冷分子研究在过去五年中迅速增长。由于低温下的热平均数会产生明显的量子效应，因此冷分子的行为预计会与高温下的分子截然不同。分子具有原子所不具备的许多特殊性质，即转动和振动运动、更长距离的多极相互作用、更丰富的空间结构和更丰富的化学反应活性。因此，冷分子的集合是化学和物理学的新前沿的宝库，任何其他方法都是完全无法实现的。然而，到目前为止，人们对冷分子的内在性质知之甚少，因为即使在1K下也很难产生分子。我的研究重点是开发新的技术来创造冷分子，并通过光谱分析来研究冷分子的物理和化学性质。我在未来五年的项目将包括四个主题：1)制造冷(0.1K)和超冷(0.1MK以下)分子的技术的发展，2)激光对冷分子的相干控制，3)量子凝聚相中分子的光谱，以及4)星际分子的天文观测。通过这些研究，将研究冷分子固有的新现象，如量子隧道效应和分子的波动性质。冷碰撞和反应散射的实验将把我们带入一个奇怪的化学新世界，即超冷化学，这可能与星际化学有关。相干控制，如利用激光场对外消旋混合物进行纯化，是冷分子需要解决的一个重要应用。其他应用包括观察手性分子中的微小能量差异，以及开发量子模拟器/计算机。分子在极低温度下的研究不仅在基础自然科学方面开辟了无限的可能性，而且在实际应用方面也提供了一个全新的物理化学研究领域。凭借我之前在冷分子研究方面的经验和新的原创性想法，我将挑战这个新兴领域，取得开创性的突破。

Cold molecule research has grown rapidly in the last five years, inspired by the success of ultracold atom research. Since pronounced quantum effects emerge from thermal averages at low temperatures, cold molecules are expected to behave quite differently from those at high temperatures. Molecules have many special features that atoms do not have, i.e. rotational and vibrational motions, longer range multipole interactions, richer spatial structures, and richer chemical reactivities. Ensembles of cold molecules are therefore a treasury of new frontiers in both chemistry and physics completely unavailable by any other means. However, little is known about the intrinsic properties of cold molecules until now because it is still difficult to create molecules even at 1 K. My research has focused on developing new techniques to create cold molecules, and investigating physical and chemical properties of cold molecules by spectroscopy. My project in the next five years will consist of four topics: 1) Development of techniques to make cold (0.1 K) and ultracold (below 0.1 mK) molecules, 2) Coherent control of cold molecules by laser fields, 3) Spectroscopy of molecules in quantum condensed phases, and 4) Astronomical observation of interstellar molecules. Through these studies, new phenomena intrinsic to cold molecules will be investigated, such as quantum tunneling effects and the wave nature of molecules. Experiments on cold collisions and reactive scattering would take us into a strange new world in chemistry, namely ultracold chemistry, which may be relevant to interstellar chemistry. Coherent control such as the enantiomeric purification of racemic mixtures by laser fields is an important application of cold molecules to be tackled. Other applications include observation of small energy differences in chiral molecules, and development of quantum simulators/computers. Studies of molecules at very low temperatures open unlimited possibilities, in terms of not only basic natural sciences, but also practical applications, which offer a completely new field of research in physical chemistry. With my previous experience on cold molecule research and new original ideas, I will challenge this newly emerging field to make a seminal breakthrough.