Demel Ondrej, Pittner Jirí
J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejskova 3, 18223 Prague 8, Czech Republic.
J Chem Phys. 2006 Apr 14;124(14):144112. doi: 10.1063/1.2192508.
We developed and implemented the state-specific Brillouin-Wigner coupled cluster method with singles, doubles, and noniterative perturbative triples, called MR BWCCSD(T), for a general number of closed- and open-shell reference configurations. To assess the accuracy of the method, we performed calculations of the three lowest electronic states of the oxygen molecule and of the automerization barrier of cyclobutadiene. For the oxygen molecule, the results were in a good agreement in comparison with those of the iterative MR BWCCSDTalpha method. For cyclobutadiene, the effect of connected triples was found to be minor, which is in agreement with the previous study by and Balková and Bartlett [J. Chem. Phys. 101, 8972 (1994)].
我们开发并实施了针对任意数量闭壳层和开壳层参考构型的、具有单双激发以及非迭代微扰三重激发的特定态布里渊-维格纳耦合簇方法，称为MR BWCCSD(T)。为评估该方法的准确性，我们对氧分子的三个最低电子态以及环丁二烯的自动异构化势垒进行了计算。对于氧分子，与迭代的MR BWCCSDTα方法的结果相比，结果吻合良好。对于环丁二烯，发现连接三重激发的影响较小，这与巴尔科娃和巴特利特之前的研究[《化学物理杂志》101, 8972 (1994)]一致。
