Mixed-sector intermediate Hamiltonian Fock-space coupled cluster approach.
Mixed-sector intermediate Hamiltonian Fock-space coupled cluster approach.
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DOI：
10.1063/1.1788652
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发表时间：
2004-10
期刊：
影响因子：
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通讯作者：
A. Landau;E. Eliav;Y. Ishikawa;U. Kaldor
中科院分区：
文献类型：
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作者：
A. Landau;E. Eliav;Y. Ishikawa;U. Kaldor
给出了以前发展的中间哈密顿Fock-空间耦合团簇格式的另一种形式。新公式的方法和计算优势包括可以使用具有属于不同Fock空间扇区的行列式的模型空间。这扩展了多参考耦合簇法的应用范围，并使得使用准闭合壳层(例如，p2，d4)作为参考态成为可能。描述了典型的应用，包括14族原子的电子亲和势，15族元素的电离势，以及银和金的电离势和激发能。得到了与实验(百分之一电子伏特)很好的一致性，与Fock空间耦合的团簇结果相比有显著的改进(对于p3态，改进了5-10倍)。现在可以研究许多用Fock-space方法无法达到的状态。
An alternative formulation of the intermediate Hamiltonian Fock-space coupled cluster scheme developed before is presented. The methodological and computational advantages of the new formulation include the possibility of using a model space with determinants belonging to different Fock-space sectors. This extends the scope of application of the multireference coupled cluster method, and makes possible the use of quasiclosed shells (e.g., p2, d4) as reference states. Representative applications are described, including electron affinities of group-14 atoms, ionization potentials of group-15 elements, and ionization potentials and excitation energies of silver and gold. Excellent agreement with experiment (a few hundredths of an electronvolt) is obtained, with significant improvement (by a factor of 5-10 for p3 states) over Fock-space coupled cluster results. Many states not reachable by the Fock-space approach can now be studied.