Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.
J Chem Phys. 2017 Oct 21;147(15):154309. doi: 10.1063/1.4997701.
An optical centrifuge is used to generate an ensemble of CO super rotors with oriented angular momentum. The collision dynamics and energy transfer behavior of the super rotor molecules are investigated using high-resolution transient IR absorption spectroscopy. New multipass IR detection provides improved sensitivity to perform polarization-dependent transient studies for rotational states with 76 ≤ J ≤ 100. Polarization-dependent measurements show that the collision-induced kinetic energy release is spatially anisotropic and results from both near-resonant energy transfer between super rotor molecules and non-resonant energy transfer between super rotors and thermal molecules. J-dependent studies show that the extent and duration of the orientational anisotropy increase with rotational angular momentum. The super rotors exhibit behavior akin to molecular gyroscopes, wherein molecules with larger amounts of angular momentum are less likely to change their angular momentum orientation through collisions.
一种光学离心机用于产生具有定向角动量的 CO 超转子系综。使用高分辨率瞬态红外吸收光谱研究了超转子分子的碰撞动力学和能量转移行为。新的多次通过 IR 检测提供了改进的灵敏度，可对具有 76≤J≤100 的旋转态进行偏振相关的瞬态研究。偏振相关测量表明，碰撞诱导的动能释放具有各向异性，这是超转子分子之间的近共振能量转移和超转子与热分子之间的非共振能量转移的结果。J 依赖性研究表明，取向各向异性的程度和持续时间随旋转角动量的增加而增加。超转子表现出类似于分子陀螺仪的行为，其中具有较大角动量的分子通过碰撞改变其角动量方向的可能性较小。
