Optical centrifuges are laser-based molecular traps that can rotationally accelerate molecules to energies rivalling or exceeding molecular bond energies. Here we report time and frequency-resolved ultrafast coherent Raman measurements of optically centrifuged CO₂ at 380 Torr spun to energies beyond its bond dissociation energy of 5.5 eV (J_max = 364, E_rot = 6.14 eV, E_rot/k_B = 71, 200 K). The entire rotational ladder from J = 24 to J = 364 was resolved simultaneously which enabled a more accurate measurement of the centrifugal distortion constants for CO₂. Remarkably, coherence transfer was directly observed, and time-resolved, during the field-free relaxation of the trap as rotational energy flowed into bending-mode vibrational excitation. Vibrationally excited CO₂ (ν₂ > 3) was observed in the time-resolved spectra to populate after 3 mean collision times as a result of rotational-to-vibrational (R-V) energy transfer. Trajectory simulations show an optimal range of J for R-V energy transfer. Dephasing rates for molecules rotating up to 5.5 times during one collision were quantified. Very slow decays of the vibrational hot band rotational coherences suggest that they are sustained by coherence transfer and line mixing.

光学离心机是基于激光的分子陷阱，可以将分子旋转加速到与分子键能相当或超过分子键能的能量。在这里，我们报告了时间和频率分辨超快相干拉曼测量的光学离心 CO ₂在 380 Torr 旋转到超过其键解离能量 5.5 eV 的能量（J _max  = 364，E _rot  = 6.14 eV，E _rot / k _B  = 71 , 200 K). 从J = 24 到J = 364的整个旋转阶梯被同时解析，这使得能够更准确地测量 CO ₂的离心畸变常数. 值得注意的是，当旋转能量流入弯曲模式振动激发时，在陷阱的无场弛豫期间直接观察到相干转移并进行时间分辨。 由于旋转到振动 (RV) 能量转移，在 3 次平均碰撞时间后，在时间分辨光谱中观察到振动激发的CO ₂ ( ν _{2 > 3)。}轨迹模拟显示了 RV 能量转移的最佳J范围。量化了在一次碰撞期间旋转多达 5.5 次的分子的相移率。振动热带旋转相干性的非常缓慢的衰减表明它们是由相干性转移和线混合维持的。