Pittner Jirí, Demel Ondrej
J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejskova 3, 18223 Prague 8, Czech Republic.
J Chem Phys. 2005 May 8;122(18):181101. doi: 10.1063/1.1885446.
We developed and implemented an approximation of the state-specific Brillouin-Wigner coupled-cluster method with singles, doubles, and triples, called MRBWCCSDT-alpha, for a general number of closed- and open-shell reference configurations. The accuracy of the method is assessed on the calculation of the oxygen molecule in the X3sigma(g-), a1delta(g), and b1sigma(g+) states and the results of this multireference treatment are compared with previous MRBWCCSD results and with those obtained by the doubly ionized similarity transformed equation-of-motion CCSD and multireference configuration interaction methods and with experimental spectroscopic data. Explicit tests of the size-extensivity of the MRBWCCSDT-alpha method with iterative size-extensivity correction are also performed.
我们开发并实施了一种针对任意数量闭壳层和开壳层参考构型的、具有单、双和三激发的特定态布里渊 - 维格纳耦合簇方法的近似方法，称为MRBWCCSDT - alpha。该方法的准确性通过对处于X3sigma(g-)、a1delta(g)和b1sigma(g+)态的氧分子进行计算来评估，并且将这种多参考处理的结果与先前的MRBWCCSD结果、通过双电离相似变换运动方程CCSD和多参考组态相互作用方法获得的结果以及实验光谱数据进行比较。还对具有迭代尺寸扩展性校正的MRBWCCSDT - alpha方法的尺寸扩展性进行了明确测试。
