Department of Chemistry, University of Gothenburg, SE-41296 Gothenburg, Sweden.
J Phys Chem B. 2011 Aug 25;115(33):10073-8. doi: 10.1021/jp2050492. Epub 2011 Jul 27.
With computational efficacy in mind, a one-center model for linear molecules is heuristically sketched. When parametrized for CO(2), all parameters save for two are supplied from literature quantum chemistry calculation or, in one case, heuristic argument. Using the remaining two adjustable parameters, the mean unsigned relative errors (predicted/observed) over the temperature range 220-290 K are 4.7% for the energy of vaporization, 0.6% for the liquid, and 8.0% for the vapor coexistence densities, respectively. The critical temperature is estimated at T(c) = 308 K, the critical density at ρ(c) = 0.460 g/cm(3), and the critical pressure at p(c) = 8.26 ± 0.11 MPa. This order of accuracy is comparable to that of many all-atom potential descriptions of CO(2) but is obtained at roughly nine times the speed. When supplied with the experimental bond length, somewhat worse agreement with experiment is exhibited for the neutron-weighted atomic pair distribution function of the liquid. This disparity is tentatively attributed to an overestimated electrostatic quadrupole-quadrupole interaction relative to the other forces present.
考虑到计算效率，我们启发式地提出了一种线性分子的单中心模型。当对 CO(2) 参数化时，除了两个参数外，所有参数都来自文献量子化学计算，或者在一种情况下，来自启发式论证。使用其余两个可调参数，在 220-290 K 的温度范围内，汽化能的平均无符号相对误差（预测/观测）分别为 4.7%，液体的为 0.6%，蒸汽共存密度的为 8.0%。临界温度估计为 T(c) = 308 K，临界密度为 ρ(c) = 0.460 g/cm(3)，临界压力为 p(c) = 8.26 ± 0.11 MPa。这种精度等级与许多 CO(2) 的全原子势描述相当，但速度快约九倍。当提供实验键长时，液体的中子加权原子对分布函数与实验的吻合稍差。这种差异暂时归因于与其他存在的力相比，静电四极矩-四极矩相互作用被高估了。
