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Title: Properties of coupled-cluster equations originating in excitation sub-algebras

Abstract

In this paper we discuss properties of single-reference coupled cluster (CC) equations associated with the existence of nilpotent sub-algebras of excitations that allow one to represent CC equations in a hybrid fashion where the cluster amplitudes associated with these sub-algebras can be obtained by solving corresponding eigenvalue problem. For closed-shell formulations analyzed in this paper, the hybrid representation of CC equations provides a natural way for extending concepts behind actives-spaces and seniority numbers to provide more accurate description of electron correlation effects. Moreover, new representation can be utilized to re-define iterative algorithms used to solve CC equations, especially for though cases defined by the presence of strong static and dynamic correlation effects. We will also explore invariance properties associated with the nilpotent sub-algebras to define a new class of CC approximations referred in this paper to as the nilpotent-flow-based CC methods. We illustrate the performance of these methods on the example of ground- and excited-state calculations for commonly used small benchmark systems.

Authors:
 [1]
  1. William R. Wiley Environmental Molecular Sciences Laboratory, Battelle, Pacific Northwest National Laboratory, K8-91, P.O. Box 999, Richland, Washington 99352, USA
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1455277
Report Number(s):
PNNL-SA-130129
Journal ID: ISSN 0021-9606; KC0310010
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 148; Journal Issue: 9
Country of Publication:
United States
Language:
English

Citation Formats

Kowalski, Karol. Properties of coupled-cluster equations originating in excitation sub-algebras. United States: N. p., 2018. Web. doi:10.1063/1.5010693.
Kowalski, Karol. Properties of coupled-cluster equations originating in excitation sub-algebras. United States. doi:10.1063/1.5010693.
Kowalski, Karol. Wed . "Properties of coupled-cluster equations originating in excitation sub-algebras". United States. doi:10.1063/1.5010693.
@article{osti_1455277,
title = {Properties of coupled-cluster equations originating in excitation sub-algebras},
author = {Kowalski, Karol},
abstractNote = {In this paper we discuss properties of single-reference coupled cluster (CC) equations associated with the existence of nilpotent sub-algebras of excitations that allow one to represent CC equations in a hybrid fashion where the cluster amplitudes associated with these sub-algebras can be obtained by solving corresponding eigenvalue problem. For closed-shell formulations analyzed in this paper, the hybrid representation of CC equations provides a natural way for extending concepts behind actives-spaces and seniority numbers to provide more accurate description of electron correlation effects. Moreover, new representation can be utilized to re-define iterative algorithms used to solve CC equations, especially for though cases defined by the presence of strong static and dynamic correlation effects. We will also explore invariance properties associated with the nilpotent sub-algebras to define a new class of CC approximations referred in this paper to as the nilpotent-flow-based CC methods. We illustrate the performance of these methods on the example of ground- and excited-state calculations for commonly used small benchmark systems.},
doi = {10.1063/1.5010693},
journal = {Journal of Chemical Physics},
number = 9,
volume = 148,
place = {United States},
year = {Wed Mar 07 00:00:00 EST 2018},
month = {Wed Mar 07 00:00:00 EST 2018}
}