The multipole polarizabilities and hyperpolarizabilities of the water molecule in liquid state:: an ab initio study
The multipole polarizabilities and hyperpolarizabilities of the water molecule in liquid state:: an ab initio study
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DOI：
10.1080/00268970110041218
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发表时间：
2001-07-01
影响因子：
1.7
通讯作者：
Kusalik, PG
中科院分区：
文献类型：
--
作者：
Gubskaya, AV;Kusalik, PG
有限场方法的电荷微扰变体已用于计算气相和液相条件下水分子的偶极矩和四极矩、偶极极化率、高阶极化率的超分量和主分量。对理论 MP2 和 MP4 水平的基态水分子进行了计算。确定的气相值允许我们测试提取极化率的方法，并选择适当平衡的、中等大小的基组；获得的结果与实验和先前最准确的理论估计非常吻合。引入局部场方法来模拟液体中水分子所经历的静电环境。在这种方法中，使用一组固定电荷来生成所需的电场和场梯度。研究了三种不同的液相模型和相应的电特性组。比较从这些模型获得的值和气相的值。从气相到液相，偶极矩和四极矩的大小增加，其中后者对液体模型的选择表现出更大的敏感性。对于液相水分子，第一超极化率 (β) 和第一较高极化率 (A) 显着增加，实际上改变了符号，第二超极化率 (γ) 也增加，但幅度不大，并且第二高阶极化率张量 (B) 的分量表现出贡献的重新排列。报告的超阶和高阶极化率张量的值是液态水的第一个此类理论估计。
A charge perturbation variant of the finite-field method has been used to calculate dipole and quadrupole moments, dipole polarizability, hyper- and principal components of high-order polarizabilities of the water molecule in gas and in liquid phase conditions. Calculations were performed for the ground-state water molecule at the MP2 and MP4 levels of theory. The gas phase values determined allow our methodology for extracting polarizabilities to be tested and a properly balanced, moderate-sized basis set to be selected; the results obtained are in very good agreement with experiment and the most accurate previous theoretical estimates. A local field approach is introduced to mimic the electrostatic environment experienced by a water molecule in the liquid. Within this approach, sets of fixed charges are used to generate the desired electric fields and field gradients. Three different liquid phase models and the corresponding sets of electrical properties are examined. The values obtained from these models and for gas-phase are compared. The magnitudes of the dipole and the quadrupole moments increase moving from gas to liquid phase, where the latter shows greater sensitivity to the choice of liquid model. For a liquid phase water molecule the first hyperpolarizability (beta) and first higher polarizability (A) increase markedly, actually changing sign, the second hyperpolarizability (gamma) also increases but much less dramatically, and components of the second high-order polarizability tensor (B) demonstrate a rearrangement of contributions. The values reported for the hyper- and high-order polarizability tensors are the first such theoretical estimates for liquid water.