The question of whether mesospheric OH(υ) rotational population distributions are in equilibrium with the local kinetic temperature has been debated over several decades. Despite several indications for the existence of non-equilibrium effects, the general consensus has been that emissions originating from low rotational levels are thermalized. Sky spectra simultaneously observing several vibrational levels demonstrated reproducible trends in the extracted OH(υ) rotational temperatures as a function of vibrational excitation. Laboratory experiments provided information on rotational energy transfer and direct evidence for fast multi-quantum OH(high-υ) vibrational relaxation by O atoms. We examine the relationship of the new relaxation pathways with the behavior exhibited by OH(υ) rotational population distributions. Rapid OH(high-υ) + O multi-quantum vibrational relaxation connects high and low vibrational levels and enhances the hot tail of the OH(low-υ) rotational distributions. The effective rotational temperatures of mesospheric OH(υ) are found to deviate from local thermodynamic equilibrium for all observed vibrational levels.

中文翻译：

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对中间层 OH 的新见解：多量子振动弛豫作为非局域热力学平衡的驱动因素

几十年来，关于中间层 OH(υ) 旋转种群分布是否与局部动力学温度平衡的问题一直存在争议。尽管有一些迹象表明存在非平衡效应，但普遍的共识是源自低旋转水平的排放是热化的。天空光谱同时观察几个振动水平表明提取的 OH(υ) 旋转温度作为振动激发的函数的可再现趋势。实验室实验提供了关于旋转能量转移的信息和 O 原子快速多量子 OH(high-υ) 振动弛豫的直接证据。我们研究了新的松弛路径与 OH(υ) 旋转种群分布所表现出的行为之间的关系。快速 OH(high-υ) + O 多量子振动弛豫连接高低振动能级并增强 OH(low-υ) 旋转分布的热尾。发现中间层 OH(υ) 的有效旋转温度偏离了所有观察到的振动水平的局部热力学平衡。