论文标题
分子比对呼应探针碰撞引起的旋转速度变化
Molecular alignment echoes probe collision-induced rotational-speed changes
论文作者
论文摘要
我们表明，随着两种激光脉冲在N2O-HE气体混合物中引起的对齐的压力衰减，并带有各种延迟，带来了有关碰撞引起的旋转速度变化的详细信息。测量和计算表明，当回声迟到时，碰撞降低了回波幅度的效率。我们通过第一个脉冲引起的经典旋转相空间的丝和细丝的逐渐变窄来定量解释这种行为。因此，回声衰减的变化反映了碰撞通过各种量改变分子旋转速度的能力，从而实现了由分子间力引起的耗散模型的精制测试。
We show that the decays with pressure of the alignment echoes induced in N2O-He gas mixtures by two laser pulses with various delays bring detailed information on collision-induced changes of the rotational speed. Measurements and calculations demonstrate that collisions reduce the echo amplitude all the more efficiently when the echo appears late. We quantitatively explain this behavior by the filamentation of the classical rotational phase space induced by the first pulse and the progressive narrowing of the filaments with time. The variation of the echo decay thus reflects the ability of collisions to change the molecules' rotational speed by various amounts, enabling refined tests of models for the dissipation induced by intermolecular forces.
