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  4. Abstract

    A high‐performance implementation of the coupled‐cluster singles, doubles, and perturbative triples [CCSD(T)] is developed in the Massively Parallel Quantum Chemistry program. Novel features include: (1) reduced memory requirements via a density‐fitting (DF) CCSD implementation utilizing distributed lazy evaluation for tensors with more than two unoccupied indices and (2) the ability to utilize efficiently many‐core nodes (Intel Xeon Phi) and heterogeneous nodes with multiple NVIDIA GPUs on each node. All data that are greater than quadratic in the system size are distributed among processes. Excellent strong scaling is observed on distributed‐memory computers equipped with conventional CPUs, Intel Xeon Phi processors, and heterogeneous nodes with multiple NVIDIA GPUs Canonical CCSD(T) energies can be evaluated for systems containing 200 electrons and 1000 basis functions in a few days using a small size commodity cluster, with even larger computations possible on leadership‐class computing resources.

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  5. Abstract

    In recent years, nonconjugated, fluorophore‐free organic polymers have emerged as potentially useful light‐emitting materials. The fluorescence properties of a novel class of nonconjugated,tert‐butyl carboxylate functionalized stilbene‐containing alternating copolymers are investigated in this work. These sterically crowded, semi‐rigid copolymers exhibit very strong blue fluorescence in organic solvents upon irradiation. The origin of the fluorescent band with high quantum yield is attributed to the “through space” π–π interactions between the phenyl rings from the stilbene and CO groups from the anhydride groups. To the best of our knowledge, the di‐tert‐butyl group‐containing stilbene and maleic anhydride alternating copolymer showed one of the highest fluorescent intensities among all fluorophore‐free polymers. The excellent linearity of the luminescence property of this copolymer is an important attribute for future potential quantitative applications. The fluorescence is maintained when thetert‐butyl groups are removed and the resulting carboxylic acid‐functionalized copolymer is dissolved in water at neutral pH, which can render these copolymers as attractive candidates for diagnostic and therapeutic applications.

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