Department of Physics, Nagoya University, Nagoya 464-8602, Japan.
J Chem Phys. 2012 Jan 28;136(4):044519. doi: 10.1063/1.3678307.
From configuration interaction (CI) ab initio calculations, we derive an effective two-orbital extended Hubbard model based on the gerade (g) and ungerade (u) molecular orbitals (MOs) of the charge-transfer molecular conductor (TTM-TTP)I(3) and the single-component molecular conductor [Au(tmdt)(2)]. First, by focusing on the isolated molecule, we determine the parameters for the model Hamiltonian so as to reproduce the CI Hamiltonian matrix. Next, we extend the analysis to two neighboring molecule pairs in the crystal and we perform similar calculations to evaluate the inter-molecular interactions. From the resulting tight-binding parameters, we analyze the band structure to confirm that two bands overlap and mix in together, supporting the multi-band feature. Furthermore, using a fragment decomposition, we derive the effective model based on the fragment MOs and show that the staking TTM-TTP molecules can be described by the zig-zag two-leg ladder with the inter-molecular transfer integral being larger than the intra-fragment transfer integral within the molecule. The inter-site interactions between the fragments follow a Coulomb law, supporting the fragment decomposition strategy.
从组态相互作用（CI）从头计算中，我们基于电荷转移分子导体（TTM-TTP）I（3）的奇偶（g）和奇（u）分子轨道（MO）和单组分分子导体[Au（tmdt）（2）]，推导出一个有效的双轨道扩展 Hubbard 模型。首先，通过聚焦于孤立分子，我们确定模型哈密顿量的参数，以便再现 CI 哈密顿量矩阵。接下来，我们将分析扩展到晶体中的两个相邻分子对，并进行类似的计算来评估分子间相互作用。从得到的紧束缚参数中，我们分析能带结构以确认两个能带重叠并混合在一起，支持多带特征。此外，使用片段分解，我们基于片段 MO 导出有效模型，并表明堆积 TTM-TTP 分子可以用具有分子间转移积分大于分子内片段转移积分的锯齿型两足梯形容纳，片段之间的相互作用遵循库仑定律，支持片段分解策略。
