title: Assessment of range-separated exchange functionals and nonempirical functional tuning for calculating the static second hyperpolarizabilities of streptocyanines.
abstract: DFT method can severely overestimate the response properties for π-conjugation systems. The range-separated exchange and recently developed optimal IP-tuning process are evaluated on the prediction of static second hyperpolarizabilities of streptocyanines of increasing molecular length. The finite field results have shown that the exact exchange at midium and long distance can relieve only a part of the overshooting but still beyond satisfaction. The exact exchange at short distance has the oppsite effects showing the failure of converntional hGGA. The optimal tuned range-separated exchange functionals show little improvements performing worse than the default ones. Importantly, the electronic structure-property relationship, bond order alternation-γ, is not well established with DFT method. © 2017 Wiley Periodicals, Inc.
authors.affiliation: MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.affiliation: Key Laboratory for Ultrafine Materials of Ministry of Education and Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, Department of Material Science and Engineering, East China University of Science and Technology, Shanghai, 200237, China.
authors.forename: Yizhong
authors.initials: Y
authors.lastname: Yuan
authors.affiliation: Key Laboratory for Ultrafine Materials of Ministry of Education and Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, Department of Material Science and Engineering, East China University of Science and Technology, Shanghai, 200237, China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Tian
keywords: RSE functionals; cyanines; optimal IP-tuning; second hyperpolarizabilities