Navrotskaya Irina, Geva Eitan
Department of Chemistry, University of Michigan, 930 North University, Ann Arbor, Michigan 48109-1055, USA.
J Chem Phys. 2007 Aug 7;127(5):054504. doi: 10.1063/1.2753155.
The calculation of vibrational energy relaxation (VER) rate constants in the condensed phase is usually based on the Landau-Teller formula, which puts them in terms of the Fourier transform, at the vibrational frequency, of the autocorrelation function of the force exerted on the relaxing mode by the bath modes. An alternative expression for the VER rate constant puts it in terms of the autocorrelation function of the vibrational energy flux. In this paper, we compare the predictions obtained via those two methods in the case of iodine in liquid xenon. We find that the computational cost underlying both methods is comparable and that they predict similar VER rates. However, while the calculation of the VER rate via the Landau-Teller formula is somewhat more direct, the predictions obtained via the flux-flux formula are in somewhat better agreement with the VER rates obtained from nonequilibrium molecular dynamics simulations.
凝聚相中振动能量弛豫（VER）速率常数的计算通常基于朗道 - 泰勒公式，该公式将其表示为在振动频率下，浴模作用于弛豫模的力的自相关函数的傅里叶变换。VER速率常数的另一种表达式是根据振动能量通量的自相关函数给出的。在本文中，我们比较了在液态氙中碘的情况下通过这两种方法获得的预测结果。我们发现这两种方法的计算成本相当，并且它们预测的VER速率相似。然而，虽然通过朗道 - 泰勒公式计算VER速率更直接一些，但通过通量 - 通量公式获得的预测结果与从非平衡分子动力学模拟得到的VER速率在某种程度上更吻合。
