The University of Osaka · 재료과학
Ryohei Kishi 교수의 연구실은 주로 분자 전자구조 이론과 고정밀 전자기계 계산을 기반으로 한 열린껍질 및 딜라디칼 시스템의 전자적 성질을 연구합니다. 특히, 두 번째 비선형 광학 응답인 이차 비선형 초극성도(gamma)의 정확한 계산을 위해 DFT 및 SF-CI 방법을 응용하며, 비균형적 전자구조와 고도로 분극화된 π-결합 시스템의 특성을 규명하고자 합니다. 최근에는 페리렌 유사체인 바이페리아주렌 유도체의 합성과 그 전자 상태 분석을 통해 이론적 예측과 실험 결과의 융합을 추구하고 있습니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
Within the spin-unrestricted density functional theory (DFT) the long-range correction (LC) scheme combined with the Becke-Lee-Yang-Parr exchange-correlation functional, referred to as LC-UBLYP method, has been applied to the calculation of the second hyperpolarizability (gamma) of open-shell singlet diradical systems of increasing complexity and has demonstrated good performance: (i) for the simplest H(2) dissociation model, the gamma values calculated by the LC-UBLYP method significantly overs
Bis-periazulene (cyclohepta[<i>def</i>]fluorene), which is an unknown pyrene isomer, was synthesized as kinetically protected forms. Its triaryl derivatives <b>1c</b>-<b>e</b> exhibited the superimposed electronic structures of peripheral, polarized, and open-shell π-conjugated systems. In contrast to previous theoretical predictions, bis-periazulene derivatives were in the singlet ground state. Changing an aryl group controlled the energy gap between the lowest singlet-triplet states.
Ab initio spin-flip configuration interaction (SF-CI) methods with the finite-field (FF) scheme are applied to the calculation of static second hyperpolarizabilities (γ) of several singlet diradical systems, i.e., the model H2 molecule under dissociation, p-quinodimethane, o-quinoid five-membered ring, and 1,4-bis(imidazole-2-ylidene)cyclohexa-2,5-diene (BI2Y) models. The SF-CI method using the UHF reference wave function provides the qualitatively correct diradical character (y) dependence of γ
