期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1982
卷号：79
期号：2
页码：705-709
DOI：10.1073/pnas.79.2.705
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Circulant, as well as canonical, orbitals are used in the different orbitals for different spins method for treating electron correlation. Circulant orbitals provide a theoretical justification for the use of a single parameter, even when the canonical orbitals have widely different orbital energies. Illustrative calculations on the ground state of the Be atom show the importance of choosing the correct "pairs" in the method. A two-parameter version of the conventional method gives 74% of the improvement obtained by a full configuration-interaction treatment using 20 linear parameters, while a one-parameter linear combination of two different coupling schemes of the circulant method gives {approx}61%. The latter wavefunction provides a compact description of the electron correlation.
关键词：alternant molecular orbital method ; beryllium atom
