Ground state energy of He isoelectronic sequence treated variationally via Hylleraas-like wavefunction

• 来源期刊: 中国物理B（英文版）
• 关键词: He isoelectronic sequence Hylleraas basis set electronic correlation variational method
• 年，卷（期）: 2009,（6）
• 页码范围: 2238-2243
• 页数: 6页
• 语种: 英文

摘要

In this study, the energy for the ground state of helium and a few helium-like ions (Z=1-6) is computed variationally by using a Hylleraas-like wavefunction. A four-parameters wavefunction, satisfying boundary conditions for coalescence points, is combined with a Hylleraas-like basis set which explicitly incorporates r12 interelectronic distance. The main contribution of this work is the introduction of modified correlation terms leading to the definition of integral transforms which provide the calculation of expectation value of energy to be done analytically over single-particle coordinates instead of Hylleraas coordinates.