Speed dependence of collisional relaxation in ground vibrational state of OCS: rotational behaviour.
Speed dependence of collisional relaxation in ground vibrational state of OCS: rotational behaviour.
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OCS 地面振动状态中碰撞松弛的速度依赖性：旋转行为。
DOI：
10.1063/1.3696895
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
J. Bouanich
中科院分区：
文献类型：
--
作者：
M. A. Koshelev;M. Tretyakov;F. Rohart;J. Bouanich
考虑到碰撞弛豫的速度依赖性，分析了(16)O(12)C(32)S纯旋转线在较大量子数J范围内压宽轮廓的精确实验数据。确定了碰撞自展宽系数的精确值，并与先前已知的数据进行了比较。获得了有关观测线形偏离传统Voigt轮廓的新的定量信息。结果表明，这些偏离主要是由碰撞弛豫的速度依赖性造成的。自展宽参数的理论计算是在半经典碰撞Robert-Bonamy形式的框架下进行的，其中考虑了平均相对分子速度以及相对速度的Maxwell-Boltzmann分布。证实了线形模型中允许速度依赖的必要性，并通过将微分截面的积分任意限制在冲击参数的有限值上，获得了满意的结果。结果表明，对于整个转动谱，速度相关模型不仅提高了对观测谱线的模拟精度，而且还给出了碰撞弛豫参数的物理基准值。
Accurate experimental data on pressure broadened profiles of (16)O(12)C(32)S pure rotational lines in a broad range of quantum number J have been analyzed taking into account the speed dependence of collisional relaxation. Refined values of collisional self-broadening coefficients are determined and compared to previously known data. New quantitative information on departures of observed line shapes from the traditional Voigt profile is obtained. It is shown that these departures result mainly from the speed dependence of collisional relaxation. Theoretical calculations of self-broadening parameters are performed in the framework of the semiclassical impact Robert-Bonamy formalism where the mean relative molecular speed as well as the Maxwell-Boltzmann distribution of relative speeds is considered. The necessity of allowance for the speed dependence in line shape models is confirmed and satisfactory results have been obtained by arbitrarily limiting the integration of the differential cross section to a finite value of the impact parameter. It is shown for the first time for the whole rotational spectrum that speed dependent models not only improve accuracy of modeling the observed line profiles but also give physically grounded values of collisional relaxation parameters.