Correlated-Participating-Orbitals Pair-Density Functional Method and Application to Multiplet Energy Splittings of Main-Group Divalent Radicals
Correlated-Participating-Orbitals Pair-Density Functional Method and Application to Multiplet Energy Splittings of Main-Group Divalent Radicals
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DOI：
10.1021/acs.jctc.6b00569
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发表时间：
2016-09-01
影响因子：
5.5
通讯作者：
Truhlar, Donald G.
中科院分区：
文献类型：
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作者：
Bao, Junwei Lucas;Sand, Andrew;Truhlar, Donald G.
预测二价自由基的单重态-三重态劈裂是电子结构理论的一项挑战性任务。在目前的工作中，我们调查的性能多组态对密度泛函理论（MC-PDFT）计算的单线态三重态分裂的小主群二价自由基，准确的实验数据是可用的。为了定义理论模型化学，可以评估一致，我们定义了三个相关的参与轨道（CPO）计划（名义上，温和的，和扩展的，缩写为名义，国防部和ext），以定义完整的活性空间的构成，我们系统地测试它们。破缺对称性Kohn-Sham DFT计算也进行了比较。我们发现，扩展CPO-PDFT计划与翻译的顶部对密度泛函有更小的平均无符号误差比加权平均破缺对称Kohn-Sham DFT与相应的交换相关泛函。翻译Perdew-Burke-Ernzerhof（tPBE）的上对密度泛函与ext-CPO活性空间的准确性甚至比我们测试的一些更准确的参数化交换相关密度泛函更好;这对MC-PDFT理论来说是非常令人鼓舞的。
Predicting the singlet-triplet splittings of divalent radicals is a challenging task for electronic structure theory. In the present work, we investigate the performance of multiconfiguration pair-density functional theory (MC-PDFT) for computing the singlet triplet splitting for small main-group divalent radicals for which accurate experimental data are available. In order to define theoretical model chemistries that can be assessed consistently, we define three correlated participating orbitals (CPO) schemes (nominal, moderate, and extended, abbreviated as nom, mod, and ext) to define the constitution of complete active spaces, and we test them systematically. Broken-symmetry Kohn-Sham DFT calculations have also been carried out for comparison. We found that the extended CPO-PDFT scheme with translated on-top pair-density functionals have smaller mean unsigned errors than weighted average broken-symmetry Kohn-Sham DFT with the corresponding exchange-correlation functional. The accuracy of the translated Perdew-Burke-Ernzerhof (tPBE) on-top pair-density functionals with ext-CPO active space is even better than some of the more accurately parametrized exchange-correlation density functionals that we tested; this is very encouraging for MC-PDFT theory.