Sorella S, Devaux N, Dagrada M, Mazzola G, Casula M
International School for Advanced Studies (SISSA), Via Beirut 2-4, 34014 Trieste, Italy and INFM Democritos National Simulation Center, Trieste, Italy.
Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Université Pierre et Marie Curie, Case 115, 4 Place Jussieu, 75252 Paris Cedex 05, France.
J Chem Phys. 2015 Dec 28;143(24):244112. doi: 10.1063/1.4938089.
We introduce an efficient method to construct optimal and system adaptive basis sets for use in electronic structure and quantum Monte Carlo calculations. The method is based on an embedding scheme in which a reference atom is singled out from its environment, while the entire system (atom and environment) is described by a Slater determinant or its antisymmetrized geminal power (AGP) extension. The embedding procedure described here allows for the systematic and consistent contraction of the primitive basis set into geminal embedded orbitals (GEOs), with a dramatic reduction of the number of variational parameters necessary to represent the many-body wave function, for a chosen target accuracy. Within the variational Monte Carlo method, the Slater or AGP part is determined by a variational minimization of the energy of the whole system in presence of a flexible and accurate Jastrow factor, representing most of the dynamical electronic correlation. The resulting GEO basis set opens the way for a fully controlled optimization of many-body wave functions in electronic structure calculation of bulk materials, namely, containing a large number of electrons and atoms. We present applications on the water molecule, the volume collapse transition in cerium, and the high-pressure liquid hydrogen.
我们介绍了一种高效的方法，用于构建用于电子结构和量子蒙特卡罗计算的最优且系统自适应的基组。该方法基于一种嵌入方案，其中从其环境中挑选出一个参考原子，而整个系统（原子和环境）由一个斯莱特行列式或其反对称双电子幂（AGP）扩展来描述。这里描述的嵌入过程允许将原始基组系统且一致地收缩为双电子嵌入轨道（GEO），对于选定的目标精度，显著减少表示多体波函数所需的变分参数数量。在变分蒙特卡罗方法中，斯莱特或AGP部分通过在存在灵活且精确的贾斯特罗因子（代表大部分动态电子关联）的情况下对整个系统的能量进行变分最小化来确定。由此产生的GEO基组为在包含大量电子和原子的块状材料的电子结构计算中对多体波函数进行完全可控的优化开辟了道路。我们展示了在水分子、铈的体积坍缩转变以及高压液态氢方面的应用。
