Coupled cluster Green function: Model involving single and double excitations
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A key aspect of this work is the determination of the frequency dependent self-energy, Σ(ω), which reveals a diagonally dominate block structure where as the non-local correlation increases, the block size increases proportionally.Abstract:
In this paper, we report on the development of a parallel implementation of the coupled-cluster (CC) Green function formulation (GFCC) employing single and double excitations in the cluster operator (GFCCSD). A key aspect of this work is the determination of the frequency dependent self-energy, Σ(ω). The detailed description of the underlying algorithm is provided, including approximations used that preserve the pole structure of the full GFCCSD method, thereby reducing the computational costs while maintaining an accurate character of methodology. Furthermore, for systems with strong local correlation, our formulation reveals a diagonally dominate block structure where as the non-local correlation increases, the block size increases proportionally. To demonstrate the accuracy of our approach, several examples including calculations of ionization potentials for benchmark systems are presented and compared against experiment.read more
Citations
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Equation-of-Motion Coupled-Cluster Cumulant Green's Function for Excited States and X-Ray Spectra.
TL;DR: In this paper, a non-perturbative real-time coupled-cluster cumulant Green's function approach has been introduced, where the Cumulant is obtained as the solution to a set of coupled first order, non-linear differential equations.
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Real-time equation-of-motion CC cumulant and CC Green's function simulations of photoemission spectra of water and water dimer.
Fernando D. Vila,John J. Rehr,Himadri Pathak,Bo Peng,Ajay Panyala,Erdal Mutlu,Nicholas P. Bauman,Karol Kowalski +7 more
TL;DR: In this article , the authors compare the results obtained with the real-time equation-of-motion CC cumulant (RT-EOM-CC) approach and CC Green's function (CCGF) approaches in applications to the water and water dimer molecules.
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Green's function coupled cluster formulations utilizing extended inner excitations
Bo Peng,Karol Kowalski +1 more
TL;DR: New approximations of the Green's function coupled cluster (GFCC) method where locations of poles are improved by extending the excitation level of inner auxiliary operators exhibit better agreement with the experimental results and other theoretical results, particularly in terms of providing higher resolution of satellite peaks and more accurate relative positions of these satellite peaks with respect to the main peak positions.
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TL;DR: The TAMM framework is described and the approach to sustainable development of tensor contraction-based methods in computational chemistry applications is described, with case studies that highlight the ease of use as well as the performance and productivity gains compared to other implementations.
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A full coupled‐cluster singles and doubles model: The inclusion of disconnected triples
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NWChem: a comprehensive and scalable open-source solution for large scale molecular simulations
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