School of Mathematics and Physics, The University of Queensland, Brisbane, QLD 4072, Australia.
J Chem Phys. 2012 Jun 21;136(23):234313. doi: 10.1063/1.4728158.
We analyze the low-energy electronic structure of a series of symmetric cationic diarylmethanes, which are bridge-substituted derivatives of Michler's Hydrol Blue. We use a four-electron, three-orbital complete active space self-consistent field and multi-state multi-reference perturbation theory model to calculate a three-state diabatic effective Hamiltonian for each dye in the series. We exploit an isolobal analogy between the active spaces of the self-consistent field solutions for each dye to represent the electronic structure in a set of analogous diabatic states. The diabatic states can be identified with the bonding structures in classical resonance-theoretic models of cyanine dyes. We identify diabatic states with opposing charge and bond-order localization, analogous to the classical resonance structures, and a third state with charge on the bridge. While the left- and right-charged structures are similar for all dyes, the structure of the bridge-charged diabatic state, and the Hamiltonian matrix elements connected to it, change significantly across the series. The change is correlated with an inversion of the sign of the charge carrier on the bridge, which changes from an electron pair to a hole as the series is traversed.
我们分析了一系列对称阳离子二芳基甲烷的低能电子结构，它们是 Michler's Hydrol Blue 的桥取代衍生物。我们使用四电子、三轨道完全活性空间自洽场和多态多参考微扰理论模型来计算该系列中每种染料的三态非绝热有效哈密顿量。我们利用自洽场解的活性空间之间的等价类比来表示一组类似的非绝热态中的电子结构。非绝热态可以与花菁染料的经典共振理论模型中的成键结构相对应。我们将具有相反电荷和键级局域化的非绝热态与经典共振结构相对应，并将第三个态与桥电荷相对应。虽然左右带电结构在所有染料中都是相似的，但桥带电非绝热态的结构以及与之相关的哈密顿矩阵元在整个系列中发生了显著变化。这种变化与桥载流子电荷符号的反转相关联，当系列被遍历时，桥载流子从电子对变为空穴。
