Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS (UMR 7583) Université Paris Est Créteil, Université Paris Diderot, Institut Pierre-Simon Laplace Université Paris Est Créteil, 94010 Créteil Cedex, France.
J Chem Phys. 2011 Mar 7;134(9):094316. doi: 10.1063/1.3557681.
Classical molecular dynamics simulations have been carried out for gaseous CO(2) starting from various anisotropic intermolecular potential energy surfaces. Through calculations for a large number of molecules treated as rigid rotors, the time evolution of the interaction-induced electric dipole vector is obtained and the Laplace transform of its autocorrelation function gives the collision-induced absorption rototranslational spectrum. The results are successfully compared with those of previous similar calculations before studies of the influences of the intermolecular potential and induced-dipole components are made. The calculated spectra show a significant sensitivity to anisotropic forces consistently with previous analyses limited to the spectral moments. The present results also demonstrate the importance of vibrational and back-induction contributions to the induced dipole. Comparisons between measured far infrared (0-250 cm(-1)) spectra at different temperatures and results calculated without the use of any adjustable parameter are made. When the best and more complete input data are used, the quality of our predictions is similar to that obtained by Gruszka et al. [Mol. Phys. 93, 1007 (1998)] after the introduction of ad hoc short-range overlap contributions. Our results thus largely obviate the need for such contributions the magnitudes of which remain questioned. Nevertheless, problems remain since, whereas good agreements with measurements are obtained above 50 cm(-1), the calculations significantly underestimate the absorption below, a problem which is discussed in terms of various possible error sources.
已经从各种各向异性的分子间势能表面出发，对气态 CO(2)进行了经典分子动力学模拟。通过对大量被视为刚性转子的分子进行计算，得到了相互作用诱导的电偶极矢量的时间演化，并通过自相关函数的拉普拉斯变换得到了碰撞诱导的吸收转动-平移光谱。在研究分子间势能和诱导偶极分量的影响之前，将这些结果与以前类似计算的结果进行了成功的比较。计算出的光谱与以前仅限于光谱矩的分析一致，对各向异性力表现出显著的敏感性。目前的结果还证明了振动和后诱导效应对诱导偶极的重要性。比较了不同温度下远红外（0-250cm(-1))的测量光谱和不使用任何可调参数计算的结果。当使用最佳和更完整的输入数据时，我们的预测质量与 Gruszka 等人[Mol. Phys. 93, 1007 (1998)]在引入特定短程重叠贡献后的结果相似。因此，我们的结果在很大程度上避免了对这些贡献的需求，这些贡献的大小仍然存在疑问。然而，仍然存在问题，因为在 50cm(-1)以上的测量结果与计算结果吻合较好，但在下面的吸收计算结果明显低估，讨论了各种可能的误差源。
