Comparative study of diradical characters and third‐order nonlinear optical properties of linear/cyclic acenes versus phenylenes. Issue 4 (16th March 2012)

• Record Type: Journal Article
• Authors: Muhammad, Shabbir; Minami, Takuya; Fukui, Hitoshi; Yoneda, Kyohei; Minamide, Shu; Kishi, Ryohei; Shigeta, Yasuteru; Nakano, Masayoshi; Nakai, Hiromi; Yoshizawa, Kazunari; Ando, Koji; Nakajima, Takahito; Brändas, Erkki J.
• Is Part Of: International journal of quantum chemistry. Volume 113:Issue 4(2013:Feb. 15)
• Page Start: 592
• Page End: 598
• Publication Date: 2012-03-16
• Subjects: Quantum chemistry -- Periodicals; 541.28
• DOI: 10.1002/qua.24032
• Languages: English
• ISSNs: 0020-7608

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A long‐range corrected spin‐unrestricted density functional theory (LC‐UDFT) approach has been used to investigate the diradical character (<italic>y</italic><sub><italic>i</italic></sub>) and third‐order nonlinear optical properties of linear/cyclic [<italic>N</italic>]acenes and [<italic>N</italic>]phenylenes in their ground states, where <italic>N</italic> is the number of benzene rings in each linear and cyclic configuration. It has been found that linear and cyclic acenes with <italic>N</italic> = 5–10 show singlet diradical characters, while linear and cyclic phenylenes with equivalent number of benzene rings have closed‐shell configurations. The amplitudes of third‐order nonlinear optical polarizability (γ<sub><italic>zzzz</italic></sub>) for open‐shell linear/cyclic acenes are larger especially in intermediate range of diradical character than those of closed‐shell phenylene counterparts. For example, the γ<sub><italic>zzzz</italic></sub> values of [5]cyclic acene (<italic>y</italic><sub>0</sub> = <italic>y</italic><sub>1</sub> = 0.320) is 4.89 × 10<sup>3</sup> a.u. which is about 6 times larger than those of 0.80 × 10<sup>3</sup> a.u. for closed‐shell [5]cyclophenylene. Similarly, γ<sub><italic>zzzz</italic></sub> value of [5]linear acene is also about 9 times larger than its closed‐shell [5]linear phenylene counterpart. Our results show interesting insights into the relationship among the architectures, diradical characters and γ<sub><italic>zzzz</italic></sub> values of different acenes and phenylenes. © 2012 Wiley Periodicals, Inc.</p> </abstract>