Excitation Energies and Properties of Open-Shell Singlet Molecules (eBook)

Masayoshi Nakano was born on January 16, 1964 in Osaka, Japan and has obtained an M. Eng. in 1988 and Ph.D. in 1991 in Chemical Engineering at Osaka University. The subject of his Ph.D. thesis was “Theoretical Studies on the Nonlinear-Optical Properties of Organic Substances”. During 1991-1992, he stayed with Prof. Keiichiro Nasu at the Institute for Molecular Science (IMS) (as JSPS Research Fellowships for Young Scientists). In 1992, he served as a research associate, in 2002 an associate professor, under the direction of Prof. Kizashi Yamaguchi in Department of Chemistry, Osaka University. In 1998, he received the 47th Young Scientist Award from the Chemical Society of Japan for “Development of non-perturbative calculation method and hyperpolarizability density analysis and molecular design of novel nonlinear optical compounds”. Since 2005, he is Professor at the Department of Materials Engineering Science, Osaka University. His research interests are quantum chemical study on the ground/excited state electronic structures and dynamics of open-shell molecular systems including nonlinear optical molecules and molecular aggregates, exciton dynamics of supramolecular systems including dendritic systems, singlet fission and quantum dynamics between atomic/molecular systems and quantized optical field using dissipative quantum mechanics. He received the “Research Excellence Award” from the European Society of Computational Methods in Science and Engineering (ESCMSE) in 2007. He has published over 250 original papers.

Preface 7
Contents 10
1 Introduction 12
Abstract 12
1.1…Classification of Electronic Structure Based on the 12
1.2…Diradical Character Based Design Principles for Nonlinear Optical Properties and 14
References 17
2 Electronic Structures of Symmetric Diradical Systems 19
Abstract 19
2.1…Symmetric Diradical Model Using the Valence 19
2.2…Diradical Character of 24
2.2.1 Diradical Character 24
2.2.2 in the Determinant Formalism with 27
2.3…Diradical Character Dependences of Excitation Energies and 31
References 36
3 Electronic Structures of Asymmetric Diradical Systems 37
Abstract 37
3.1…Asymmetric Diradical Model Using the Valence Configuration Interaction Method 37
3.2…Asymmetricity of the Neutral and as well as of the 42
3.3…Asymmetricity (rh) Dependences of the Excitation Energies and Excitation Properties for Different Pseudo yS 47
References 51
4 Diradical Character View of (Non)Linear Optical Properties 52
Abstract 52
4.1…(Non)Linear Optical Properties: (Hyper)Polarizabilities 52
4.2…Second Hyperpolarizability ( gamma ) for Symmetric 56
4.3…One-Photon Absorption for Symmetric Systems 61
4.4…Two-Photon Absorption for Symmetric Systems 62
4.5…First Hyperpolarizability ( beta ) for 66
4.6…Second Hyperpolarizability ( gamma ) for Asymmetric 68
4.7… ( gamma ) for 72
4.7.1 , Multiple Diradical Character, and in the Perturbative Expression of gamma 73
4.7.2 Effect of the on gamma 74
4.7.3 Effect of the on gamma 74
4.8…Examples of Open-Shell Singlet Molecular Systems 78
References 85
5 Diradical Character View of Singlet Fission 87
Abstract 87
5.1…Singlet Fission 87
5.1.1 Singlet Fission from the Viewpoint of 87
5.1.2 Kinetic Scheme of Singlet Fission 89
5.1.3 Molecular Design Guidelines: 95
5.1.3.1 Alternant Hydrocarbon as a Closed-Shell Parent 96
5.1.3.2 Diradical Molecule as an Open-Shell Parent 97
5.2…Diradical Character View of Singlet Fission Based on 99
5.2.1 Introduction 99
5.2.2 99
5.2.3 Relationship between Multiple Diradical Character and Excitation Energies in 101
5.2.4 Diradical Character Based Molecular Design Guideline for 105
5.3…[n]Acenes and [n] 110
5.3.1 Introduction 110
5.3.2 Analytical Relationship between Energy Matching Condition and 112
5.3.3 Computational Details 114
5.3.4 Difference in Excitation Energies between [n]Acenes and [n] 115
5.3.5 Summary 118
References 119
6 Summary and Future Prospects 121
Abstract 121
References 124
Index 125