A high external quantum efficiency observed for organic light-emitting diodes using PTZ-BZP (PTZ: 10-hexyl-phenothiazin, and BZP:4-phenyl-2,1,3-benzothiadiazole) is attributed to fluorescence from S1 via reverse intersystem crossing from the T3 or T2 state under electrical excitation. The radiative and non-radiative transitions from these higher triplet states to the lower triplet states are suppressed because of their small overlap densities. In this study, a principle to design such an electronic structure is proposed.

Recently, studies of solar cells have been conducted actively. Especially, organic thin film solar cells are attracting attention for use as a next-generation flexible substrate material. The reasons include the recent advent of bulk heterojunction structures. Nevertheless, bulk heterojunction solar cells exhibit only about 10% conversion efficiency. They have remained in the study phase. One reason for their low conversion efficiency is that a bulk heterojunction conductive mechanism is so complicated that its fundamental electronic properties have not been elucidated well. This letter describes an examination of the excited state of the bulk heterojunction structure and evaluates its electronic properties. Charge densities are computed for excited and ground states. Then absorbance is computed and examined. Results suggest that the electronically excited state might come to differ from the electronic ground state in a phthalocyanine–fullerene bimolecular system. Moreover, we infer that this behavior brings about energy level change and subsequent variation in absorbance.

We recently proposed a real-time simulation method of nuclear and electron wave packet molecular dynamics (NEWPMD) based on wave functions of hydrogen molecules composed of nuclear and electron WPs. Non-empirical intra- and intermolecular interactions of non-spherical hydrogen molecules were explicitly derived and a long-range dispersion force between hydrogen molecules was successfully derived. Nuclear quantum effects (NQEs) such as nuclear delocalization and zero-point energy were non-perturbatively taken into account. The developed NEWPMD method can be applied to various condensed hydrogen systems from a gas-phase to a high-pressure solid phase at feasible computational cost, providing intuitive understandings of real-time dynamics of each hydrogen molecule including H-H bond vibration, molecular orientations and librational motions. We will report the demonstrations not only in liquid hydrogens but also in solid and supercooled hydrogens which exhibited strong NQEs and thus anomalous static and dynamic properties.

プロトン(水素原子)と電子の相関現象は，生体系や各種の化学反応において重要な役割を担っている．その一方で，固体結晶中においてこのような相関現象はこれまでほとんど見つかっていなかった．筆者らは，有機伝導体を舞台とした独自の物質開発研究を展開し，最近，水素結合中の水素原子ダイナミクスと有機π電子の連動・相関に起因する前例のない大変ユニークな動的現象・機能物性を発見した．本稿では，このπ電子系固体物質における新しい「量子水素の科学」を物質開発ならびに水素/重水素同位体効果の観点から紹介したい．

Aromatic molecules form stable charge-transfer complexes with quinones, tetracyanoethylene or halogen molecules. The charge-transfer interaction (orbital-orbital interaction) was believed to be the source of the attraction in the complexes. However, the contributions of other intermolecular interactions (dispersion, electrostatic etc.) to the attraction in the complexes are not well understood. The total interaction energy and contributions of electrostatic, induction, dispersion and orbital-orbital (exchange-repulsion and charge-transfer) interactions in the benzene-p-benzoquinone complex were studied by ab initio molecular orbital calculations. The analysis shows that the dispersion interaction is the major source of the attraction in the complex and that the orbital-orbital interaction is not attractive but even repulsive.

核・電子軌道 (NOMO) 法は，原子核に対して軌道の概念を導入した量子化学理論である．NOMO法におけるHartree-Fock (HF)方程式の解として得られる原子核軌道エネルギーは，全エネルギーや軌道そのものと比較して注目されていない．本論文では，NOMO法における原子核軌道エネルギーの物理的意味とpost-HF理論への応用を述べる．特に，最近開発されたプロトンプロパゲーター法による束縛エネルギーの見積りについて，計算例を含めて紹介する．

Molecular dynamics simulation of 4-n-alkyl-4'-cyanobiphenyl series (nCB) using the full-atom model was carried out. We used a force field that was fitting the dihedral angle parameter and the LJ parameters of the AMBER Force Field against nCB. The dihedral angle parameter is set to reference the quantum chemical calculation, and the LJ parameters were fitted to reproduce the experimental data. By using the modified force field, experimental data such as isotropic-nematic phase transition temperature and density were reproduced.

Misleading classification of isomeric and stereoisomeric relationships as well as the related misleading classification of isomers and stereoisomers are discussed in terms of equivalence relationships and equivalence classes, which have not been taken into consideration in the conventional terminology of modern stereochemistry.

GPU acceleration for OpenFMO, a fragment molecular orbital calculation program, has been implemented and its performance was examined. We have developed a GPU-accelerated Fock matrix preparation routine without atomic operation and implemented it into the worker module of an OpenFMO program, which is parallelized in a master-worker programming model. The GPU-accelerated program shows 1.5× speedups from CPU only FMO-HF/6-31G (d) calculation with a direct SCF method for 642 atomic protein on 8 nodes of HA-PACS base cluster.