TY - JOUR
T1 - Identifying Electronic Modes by Fourier Transform from δ-Kick Time-Evolution TDDFT Calculations
AU - Sinha-Roy, Rajarshi
AU - García-González, Pablo
AU - López Lozano, Xóchitl
AU - Whetten, Robert L.
AU - Weissker, Hans Christian
N1 - Funding Information:
Enlightening discussions with Antonio I. Fernańdez Domıńguez are gratefully acknowledged. We are grateful to Franck Rabilloud for providing us the LR-TDDFT results for Na55 as well as for helpful discussions. This work has been carried out thanks to the support of the A*MIDEX grant (no. ANR-11-IDEX-0001-02) funded by the French Government “Investissements d’Avenir” program. We acknowledge support from the French National Research Agency (Agence Nationale de Recherche, ANR) in the frame of the project “FIT SPRINGS”, ANR-14-CE08-0009. This work has used HPC resources from GENCI-IDRIS (Grant 2016-096829). P.G.-G. acknowledges funding from the Spanish MINECO through the “Marıá de Maeztu” programme for Units of Excellence in R&D (MDM-2014-0377) and through the research grant MAT2014-53432-C5-5-R.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/12/11
Y1 - 2018/12/11
N2 - Time-dependent density-functional theory (TDDFT) is widely used for calculating electron excitations in clusters and large molecules. For optical excitations, TDDFT is customarily applied in two distinct approaches: transition-based linear-response TDDFT (LR-TDDFT) and the real-time formalism (RT-TDDFT). The former directly provides the energies and transition densities of the excitations, but it requires the calculation of a large number of empty electron states, which makes it cumbersome for large systems. By contrast, RT-TDDFT circumvents the evaluation of empty orbitals, which is especially advantageous when dealing with large systems. A drawback of the procedure is that information about the nature of individual spectral features is not automatically obtained, although it is of course contained in the time-dependent induced density. Fourier transform of the induced density has been used in some simple cases, but the method is, surprisingly, not widely used to complement the RT-TDDFT calculations; although the reliability of RT-TDDFT spectra is now widely accepted, a critical assessment for the corresponding transition densities and a demonstration of the technical feasibility of the Fourier-transform evaluation for general cases is still lacking. In the present work, we show that the transition densities of the optically allowed excitations can be efficiently extracted from a single δ-kick time-evolution calculation even in complex systems like noble metals. We assess the results by comparison with the corresponding LR-TDDFT ones and also with the induced densities arising from RT-TDDFT simulations of the excitation process.
AB - Time-dependent density-functional theory (TDDFT) is widely used for calculating electron excitations in clusters and large molecules. For optical excitations, TDDFT is customarily applied in two distinct approaches: transition-based linear-response TDDFT (LR-TDDFT) and the real-time formalism (RT-TDDFT). The former directly provides the energies and transition densities of the excitations, but it requires the calculation of a large number of empty electron states, which makes it cumbersome for large systems. By contrast, RT-TDDFT circumvents the evaluation of empty orbitals, which is especially advantageous when dealing with large systems. A drawback of the procedure is that information about the nature of individual spectral features is not automatically obtained, although it is of course contained in the time-dependent induced density. Fourier transform of the induced density has been used in some simple cases, but the method is, surprisingly, not widely used to complement the RT-TDDFT calculations; although the reliability of RT-TDDFT spectra is now widely accepted, a critical assessment for the corresponding transition densities and a demonstration of the technical feasibility of the Fourier-transform evaluation for general cases is still lacking. In the present work, we show that the transition densities of the optically allowed excitations can be efficiently extracted from a single δ-kick time-evolution calculation even in complex systems like noble metals. We assess the results by comparison with the corresponding LR-TDDFT ones and also with the induced densities arising from RT-TDDFT simulations of the excitation process.
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U2 - 10.1021/acs.jctc.8b00750
DO - 10.1021/acs.jctc.8b00750
M3 - Article
C2 - 30404453
AN - SCOPUS:85058157694
VL - 14
SP - 6417
EP - 6426
JO - Journal of Chemical Theory and Computation
JF - Journal of Chemical Theory and Computation
SN - 1549-9618
IS - 12
ER -