Computational Chemistry Research Group , Ton Duc Thang University , Ho Chi Minh City , 700000 Vietnam.
Faculty of Applied Sciences , Ton Duc Thang University , Ho Chi Minh City , 700000 Vietnam.
J Chem Theory Comput. 2018 Sep 11;14(9):4833-4843. doi: 10.1021/acs.jctc.8b00412. Epub 2018 Aug 7.
Geometrical and electronic structures of the chromium oxide dimer in both charge states CrO were carefully and thoroughly studied using the restricted active space RASSCF/RASPT2 and density matrix renormalization group followed by second-order perturbation theory DMRG-CASPT2 methods in conjunction with large basis sets. The anionic and neutral clusters CrO are characterized by a D structure and high-spin ground states (10 and 9, respectively). RASSCF wave functions point out strong multireference characters of their electronic ground state. The two lowest-lying states A and B of the anion CrO are nearly degenerate, and both were proven to be populated and involved in the anion photoelectron spectra of CrO. The neutral cluster exhibits a B ground state. Within the active space of 20 electrons in 18 orbitals used, 30 electronic transitions starting from both lower-lying anionic states to corresponding neutral states were predicted. Transitions from the anionic ground state A cause most of visible bands in the anion photoelectron spectra of CrO, while the first band with low intensity is determined to arise from a transition starting from the nearly degenerate state B. Furthermore, multidimensional Franck-Condon factor simulations were carried out to further support our band assignments.
使用受限活性空间 RASSCF/RASPT2 和密度矩阵重整化群加上二阶微扰理论 DMRG-CASPT2 方法，并结合大基组，仔细而彻底地研究了两种电荷态 CrO 中氧化铬二聚体的几何和电子结构。阴离子和中性团簇 CrO 具有 D 结构和高自旋基态（分别为 10 和 9）。RASSCF 波函数指出其电子基态具有强烈的多参考特征。阴离子 CrO 的两个最低能级 A 和 B 几乎简并，并且都被证明在 CrO 的阴离子光电子能谱中被占据和参与。中性团簇表现出 B 基态。在所使用的 20 个电子 18 轨道的活性空间内，预测了从较低的阴离子态到相应的中性态的 30 个电子跃迁。从阴离子基态 A 引起的跃迁导致了 CrO 的阴离子光电子能谱中的大多数可见带，而强度较低的第一个带被确定是由来自几乎简并态 B 的跃迁引起的。此外，进行了多维 Franck-Condon 因子模拟以进一步支持我们的带分配。
