Ramos-Berdullas Nicolás, Gil-Guerrero Sara, Peña-Gallego Ángeles, Mandado Marcos
Department of Physical Chemistry, University of Vigo, Lagoas-Marcosende s/n, 36310, Vigo, Spain.
Phys Chem Chem Phys. 2021 Feb 28;23(8):4777-4783. doi: 10.1039/d0cp06321e. Epub 2021 Feb 18.
Some of the most promising materials for application in molecular electronics and spintronics are based on diradical chains. Herein, the proposed relation between increasing conductance with length and diradical character is revisited using ab initio methods that account for the static electron correlation effects. Electron transmission was previously obtained from restricted single determinant wavefuntions or tight-binding approximations, which are unable to account for static correlation. Broken Symmetry Unrestricted Kohn-Sham Density Functional Theory (BS-UKS-DFT) in combination with electron transport analysis based on electron deformation orbitals (EDOs) reflects an exponential decay of the electrical conductance with length. Also, other important effects such as quantum interference are correctly accounted for, leading to a decrease of the conductance as the diradical character increases. As a proof-of-concept, the electrical conductance obtained from BS-UKS-DFT and CASSCF(2,2) wavefunctions were compared in diradical graphene strips in the frame of the pseudo-π approach, obtaining very similar results.
一些在分子电子学和自旋电子学中最具应用前景的材料是基于双自由基链的。在此，使用考虑了静态电子相关效应的从头算方法，重新审视了所提出的电导随长度增加与双自由基特性之间的关系。电子传输先前是从受限单行列式波函数或紧束缚近似中获得的，而这些方法无法考虑静态相关。破缺对称性无限制Kohn-Sham密度泛函理论（BS-UKS-DFT）与基于电子变形轨道（EDO）的电子输运分析相结合，反映了电导随长度呈指数衰减。此外，诸如量子干涉等其他重要效应也得到了正确考虑，导致随着双自由基特性增加电导降低。作为概念验证，在赝π方法框架下，比较了从BS-UKS-DFT和CASSCF(2,2)波函数获得的双自由基石墨烯条带的电导，得到了非常相似的结果。
