1,395 research outputs found

    Intramolecular dynamics. III. Theoretical studies of the CH overtone spectra for benzene

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    The electronic states of the ionic excimer Ar + + 2 are calculated using ab initio multireference configuration interaction and effective core pseudopotentials. Among states dissociating into Ar+(2P)+Ar+(2P), all are found to be repulsive, except the ground state, which occurs to be quasibound near Re=4.1a0 with a well depth of >=230 cm^βˆ’1. All states originating from Ar++(3P,1D,1S)+Ar are bound with dissociation energies in the range 3200–4500 cm^βˆ’1 and equilibrium distances between 5.6a0 and 6a0. Simulation emission spectra from bound excited states are derived from the calculated potentials and the possible contribution of the Ar + + 2 ion to the third continuum fluorescence is discussed

    Learning over Knowledge-Base Embeddings for Recommendation

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    State-of-the-art recommendation algorithms -- especially the collaborative filtering (CF) based approaches with shallow or deep models -- usually work with various unstructured information sources for recommendation, such as textual reviews, visual images, and various implicit or explicit feedbacks. Though structured knowledge bases were considered in content-based approaches, they have been largely neglected recently due to the availability of vast amount of data, and the learning power of many complex models. However, structured knowledge bases exhibit unique advantages in personalized recommendation systems. When the explicit knowledge about users and items is considered for recommendation, the system could provide highly customized recommendations based on users' historical behaviors. A great challenge for using knowledge bases for recommendation is how to integrated large-scale structured and unstructured data, while taking advantage of collaborative filtering for highly accurate performance. Recent achievements on knowledge base embedding sheds light on this problem, which makes it possible to learn user and item representations while preserving the structure of their relationship with external knowledge. In this work, we propose to reason over knowledge base embeddings for personalized recommendation. Specifically, we propose a knowledge base representation learning approach to embed heterogeneous entities for recommendation. Experimental results on real-world dataset verified the superior performance of our approach compared with state-of-the-art baselines

    Intramolecular dynamics. I. Curvilinear normal modes, local modes, molecular anharmonic Hamiltonian, and application to benzene

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    The Hamiltonian based on curvilinear normal modes and local modes (CNLM) is discussed using Wilson's exact vibrational Hamiltonian as basis, the CNLM representation diagonalizing only the normal mode block of FG matrix in curvilinear internal coordinates. Using CNLM the kinetic and potential energy operators for benzene are given, including cubic and quartic anharmonicity in the potential energy and cubic and quartic terms in the kinetic energy expansion in curvilinear coordinates. Using symmetrized coordinates and cubic and higher force constants the number and identity of the independent symmetry allowed (A1g) such force constants are obtained. The relation to conventional anharmonic force constants is then given and the allowed contributions of the latter are obtained. The results are applied to CH overtone spectra and intramolecular vibrational dynamics in Part III of this series
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