Inclusion of explicit electron-proton correlation in the nuclear-electronic orbital approach using Gaussian-type geminal functions
Inclusion of explicit electron-proton correlation in the nuclear-electronic orbital approach using Gaussian-type geminal functions
复制标题
DOI：
10.1063/1.2943144
复制
发表时间：
2008-07-07
影响因子：
4.4
通讯作者：
Hammes-Schiffer, Sharon
中科院分区：
文献类型：
--
作者：
Chakraborty, Arindam;Pak, Michael V.;Hammes-Schiffer, Sharon
提出了一种在混合核电子波函数中考虑电子-质子关联的核电子轨道显关联Hartree-Fock（NEO-XCHF）方法。本文提出了一个核电子波函数的一般解析式，它包含了核电子距离与高斯型孪函数的显式依赖关系。在此基础上，导出了多电子系统的总能量、电子和核Fock算符的表达式。显式的电子-质子相关直接纳入自洽场程序优化的核电子波函数。这种方法对于多电子系统在计算上是实用的，因为只有相对少量的原子核被量子力学地处理，并且只有电子-质子关联被明确地处理。电子-电子关联可以包括通过结合微扰理论，密度泛函理论，和多组态方法的NEO-XCHF方法。以前基于核电子轨道的方法产生的核密度过于局部化，导致异常高的拉伸频率和依赖于这些密度的其他属性的不准确性。NEO-XCHF方法在[He-H-He]（+）模型系统中的应用表明，该方法包含了重要的电子-质子关联，从而导致对核密度的准确描述。NEO-XCHF方法和网格方法获得的质子密度之间的一致性验证了NEO-XCHF方法的基本理论和实施。(c)2008年美国物理研究所。
The nuclear-electronic orbital explicitly correlated Hartree-Fock (NEO-XCHF) approach for including electron-proton correlation in mixed nuclear-electronic wavefunctions is presented. A general ansatz for the nuclear-electronic wavefunction that includes explicit dependence on the nuclear-electronic distances with Gaussian-type geminal functions is proposed. Based on this ansatz, expressions are derived for the total energy and the electronic and nuclear Fock operators for multielectron systems. The explicit electron-proton correlation is incorporated directly into the self-consistent-field procedure for optimizing the nuclear-electronic wavefunction. This approach is computationally practical for many-electron systems because only a relatively small number of nuclei are treated quantum mechanically, and only electron-proton correlation is treated explicitly. Electron-electron correlation can be included by combining the NEO-XCHF approach with perturbation theory, density functional theory, and multiconfigurational methods. Previous nuclear-electronic orbital-based methods produce nuclear densities that are too localized, resulting in abnormally high stretching frequencies and inaccuracies in other properties relying on these densities. The application of the NEO-XCHF approach to the [He-H-He](+) model system illustrates that this approach includes the significant electron-proton correlation, thereby leading to an accurate description of the nuclear density. The agreement between the proton densities obtained with the NEO-XCHF and grid-based methods validates the underlying theory and the implementation of the NEO-XCHF method. (c) 2008 American Institute of Physics.