Theoretical studies on optical activities of helical polymers based on localized orbitals under the periodic boundary condition

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K05392
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 32010:Fundamental physical chemistry-related
• Research Institution: Tokyo Denki University
• Principal Investigator: Hatanaka Masashi 東京電機大学, 工学部, 助教 (40772778)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: らせん高分子 / 光学活性 / 量子化学 / 結晶軌道法 / ワニエ関数 / サイズ効果 / 異方性

Outline of Final Research Achievements

In light of recent advances in the science of helical polymers, the optical activities of them were deduced under the periodic boundary condition with localized orbitals (Wannier functions). The optical rotatory strength was attributed to interactions between localized Wannier functions around each cell, and the optical activities of helical polyacetylene were quantitatively reproduced. Based on this theory, size effect of the optical rotatory strength was correctly interpreted. In addition, this theory was extended to general three-dimensional crystals, and theory of the anisotropic optical activities was established. On the other hand, we attempted to apply the theory above to synthetic poly(acrylic acid) and polyuret, which is the fundamental skeleton of helical polymers, and some related compounds led to new magnetic properties and intriguing tautomerism.

Free Research Field

物理化学

Academic Significance and Societal Importance of the Research Achievements

本研究はらせん高分子の光学活性に関する理論的定式化を行うものであり、結晶軌道法に基づいた量子化学的手法によりその旋光強度を定量的に導出することを目指して遂行された。その方法は周期的境界条件下で実数の局在化軌道（ワニエ関数）を用いることを特徴としており、光学活性はそれらの相互作用の和として表現されるため、当該分野の基礎的な学理として化学的直観に優れた見通しを与える。本研究はらせん高分子の光学活性におけるサイズ効果への応用、さらに一般の３次元結晶における異方性光学活性の理論への拡張につながった。とくに後者は国際的にも未達成の課題であるためその意義は大きく、結晶光学への広汎な応用が期待される。