Exchange functionals with improved long-range behavior and adiabatic connection methods without adjustable parameters:: The mPW and mPW1PW models
Exchange functionals with improved long-range behavior and adiabatic connection methods without adjustable parameters:: The mPW and mPW1PW models
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DOI：
10.1063/1.475428
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发表时间：
1998-01-08
影响因子：
4.4
通讯作者：
Barone, V
中科院分区：
文献类型：
--
作者：
Adamo, C;Barone, V
从对主导范德华相互作用的低密度和大梯度区域的分析出发，我们提出对Perdew和Wang引入的交换泛函进行修改，这显著扩大了其应用领域。这是在不增加可调参数数量且保留原始模型所有渐近和标度性质的情况下实现的。将新的交换泛函与Perdew和Wang也提出的相关泛函耦合，得到了mPWPW模型，它代表了迄今为止可用的最精确的广义梯度近似。接下来我们引入一种绝热连接方法，其中精确交换与密度泛函交换之间的比率是根据纯理论考虑先验确定的，并且不存在更多参数。由此产生的mPW1PW模型能够在一个相当令人满意的理论框架内，对于共价和非共价相互作用都获得显著的结果，该理论框架涵盖了自由电子气极限和大多数已知的标度条件。新的泛函及其导数已在高斯系列程序中编码，从而能够对能量和性质进行完全自洽的计算，以及对一阶和二阶几何导数进行解析评估。（C）1998美国物理学会
Starting from an analysis of the low-density and large gradient regions which dominate van der Waals interactions, we propose a modification of the exchange functional introduced by Perdew and Wang, which significantly enlarges its field of applications, This is obtained without increasing the number of adjustable parameters and retaining all the asymptotic and scaling properties of the original model. Coupling the new exchange functional to the correlation functional also proposed by Perdew and Wang leads to the mPWPW model, which represents the most accurate generalized gradient approximation available until now, We next introduce an adiabatic connection method in which the ratio between exact and density functional exchange is determined a priori from purely theoretical considerations and no further parameters are present. The resulting mPW1PW model allows to obtain remarkable results both for covalent and noncovalent interactions in a quite satisfactory theoretical framework encompassing the free electron gas limit and most of the known scaling conditions. The new functionals have been coded with their derivatives in the Gaussian series of programs, thus allowing fully self-consistent computations of energy and properties together with analytical evaluation of first and second geometry derivatives. (C) 1998 American Institute of Physics.