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Organic Nonlinear Optical Materials: The Mechanism of Intermolecular Covalent Bonding Interactions of Kekulé Hydrocarbons with Significant Singlet Biradical Character
Author(s) -
Liu Jing,
Xia Jiarui,
Song Peng,
Ding Yong,
Cui Yanling,
Liu Xuemei,
Dai Yumei,
Ma Fengcai
Publication year - 2014
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201402026
Subject(s) - chemistry , van der waals force , intermolecular force , density functional theory , singlet state , molecule , chemical physics , covalent bond , excited state , homo/lumo , linker , computational chemistry , photochemistry , atomic physics , organic chemistry , physics , computer science , operating system
Abstract The ground‐ and excited‐state properties of benzene‐linked bisphenalenyl (B‐LBP), naphthaline‐linked bisphenalenyl (N‐LBP), and anthracene‐linked bisphenalenyl (A‐LBP) Kekulé molecules and their respective one‐dimensional (1D) stacks are investigated using time‐dependent density functional theory (TD‐DFT) and a range of extensive multidimensional visualization techniques. The results reveal a covalent π–π bonding interaction between overlapping phenalenyl radicals whose bond length is shorter than the van der Waals distance between carbon atoms. Increasing the linker length and/or number of molecules involved in the 1D stack decreases the HOMO–LUMO energy gap and increases the wavelength of the systems. The charge‐transfer mechanism and electron coherence both differ with changes in the linker length and/or number of molecules involved in the 1D stack.