Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583, Universités Paris Est Créteil et Paris Diderot, Institut Pierre-Simon Laplace, Université Paris Est Créteil, 94010 Créteil Cedex, France.
J Chem Phys. 2013 Jun 28;138(24):244310. doi: 10.1063/1.4811518.
Ab initio calculations of the shapes of pure CO2 infrared and Raman bands under (pressure) conditions for which line-mixing effects are important have been performed using requantized classical molecular dynamics simulations. This approach provides the autocorrelation functions of the dipole vector and isotropic polarizability whose Fourier-Laplace transforms yield the corresponding spectra. For that, the classical equations of dynamics are solved for each molecule among several millions treated as linear rigid rotors and interacting through an anisotropic intermolecular potential. Two of the approximations used in the previous studies have been corrected, allowing the consideration of line-mixing effects without use of any adjusted parameters. The comparisons between calculated and experimental spectra under various conditions of pressure and temperature demonstrate the quality of the theoretical model. This opens promising perspectives for first principle ab initio predictions of line-mixing effects in absorption and scattering spectra of various systems involving linear molecules.
使用重新量子化的经典分子动力学模拟，对在对混合线效应很重要的（压力）条件下纯 CO2 的红外和拉曼带的形状进行了从头计算。该方法提供了偶极子矢量和各向同性极化率的自相关函数，其傅立叶 - 拉普拉斯变换给出了相应的光谱。为此，针对作为线性刚性转子处理的数百万个分子中的每个分子求解了经典动力学方程，并通过各向异性的分子间势能进行相互作用。先前研究中使用的两个近似已被修正，从而可以在不使用任何调整参数的情况下考虑混合线效应。在不同压力和温度条件下计算光谱与实验光谱之间的比较表明了理论模型的质量。这为涉及线性分子的各种系统的吸收和散射光谱中的混合线效应的从头算 ab initio 预测开辟了有希望的前景。
