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Title: Cluster formation in precompound nuclei in the time-dependent framework

Publication Date:
Sponsoring Org.:
OSTI Identifier:
Grant/Contract Number:
DOE-DE-NA0002847; SC0008511; SC0013365
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review C
Additional Journal Information:
Journal Volume: 96; Journal Issue: 6; Related Information: CHORUS Timestamp: 2017-12-15 10:32:48; Journal ID: ISSN 2469-9985
American Physical Society
Country of Publication:
United States

Citation Formats

Schuetrumpf, B., and Nazarewicz, W. Cluster formation in precompound nuclei in the time-dependent framework. United States: N. p., 2017. Web. doi:10.1103/PhysRevC.96.064608.
Schuetrumpf, B., & Nazarewicz, W. Cluster formation in precompound nuclei in the time-dependent framework. United States. doi:10.1103/PhysRevC.96.064608.
Schuetrumpf, B., and Nazarewicz, W. 2017. "Cluster formation in precompound nuclei in the time-dependent framework". United States. doi:10.1103/PhysRevC.96.064608.
title = {Cluster formation in precompound nuclei in the time-dependent framework},
author = {Schuetrumpf, B. and Nazarewicz, W.},
abstractNote = {},
doi = {10.1103/PhysRevC.96.064608},
journal = {Physical Review C},
number = 6,
volume = 96,
place = {United States},
year = 2017,
month =

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on December 15, 2018
Publisher's Accepted Manuscript

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  • We study time-dependent coupled-cluster theory in the framework of nuclear physics. Based on Kvaal's bi-variational formulation of this method [S. Kvaal, arXiv:1201.5548], we explicitly demonstrate that observables that commute with the Hamiltonian are conserved under time evolution. We explore the role of the energy and of the similarity-transformed Hamiltonian under real and imaginary time evolution and relate the latter to similarity renormalization group transformations. Proof-of-principle computations of He-4 and O-16 in small model spaces, and computations of the Lipkin model illustrate the capabilities of the method
  • This article presents a time dependent density functional theory (TDDFT) implementation to propagate the Kohn-Sham equations in real time, including the effects of a molecular environment through a Quantum-Mechanics Molecular-Mechanics (QM-MM) hamiltonian. The code delivers an all-electron description employing Gaussian basis functions, and incorporates the Amber force-field in the QM-MM treatment. The most expensive parts of the computation, comprising the commutators between the hamiltonian and the density matrix—required to propagate the electron dynamics—, and the evaluation of the exchange-correlation energy, were migrated to the CUDA platform to run on graphics processing units, which remarkably accelerates the performance of the code.more » The method was validated by reproducing linear-response TDDFT results for the absorption spectra of several molecular species. Two different schemes were tested to propagate the quantum dynamics: (i) a leap-frog Verlet algorithm, and (ii) the Magnus expansion to first-order. These two approaches were confronted, to find that the Magnus scheme is more efficient by a factor of six in small molecules. Interestingly, the presence of iron was found to seriously limitate the length of the integration time step, due to the high frequencies associated with the core-electrons. This highlights the importance of pseudopotentials to alleviate the cost of the propagation of the inner states when heavy nuclei are present. Finally, the methodology was applied to investigate the shifts induced by the chemical environment on the most intense UV absorption bands of two model systems of general relevance: the formamide molecule in water solution, and the carboxy-heme group in Flavohemoglobin. In both cases, shifts of several nanometers are observed, consistently with the available experimental data.« less
  • We present an algorithm for Monte-Carlo selection of exciton energies for reactions induced by clusters. Reaction mechanisms are addressed that involve a dissolution of the cluster into its constituent nucleons followed by the initiation of a preequilibrium cascade. Calculated single differential spectra and excitation functions for {sup 93}Nb({alpha},xn) reactions are compared with experimental results to illustrate use of this method. Some advantages of exclusive computational techniques over analytic inclusive methods are summarized. (c) 2000 The American Physical Society.