TY - JOUR
T1 - Pulse shape and molecular orientation determine the attosecond charge migration in Caffeine
AU - Niehaus, Thomas A.
AU - Meziane, Mehdi
AU - Lepine, Franck
AU - Marciniak, Alexandre
AU - Yamazaki, Kaoru
AU - Kono, Hirohiko
N1 - Funding Information:
T.N. would like to thank the Laboratoire d’Excellence iMUST and the fund BQR Accueil EC 2016 for financial support. K. Y.
Funding Information:
is grateful for the financial supports from Building of Consortia for the Development of Human Resources in Science and Technology by the Ministry of Education, Culture, Sports, Science and Technology (MEXT).
Publisher Copyright:
© 2018, EDP Sciences, SIF, Springer-Verlag GmbH Germany, part of Springer Nature.
PY - 2018/7/1
Y1 - 2018/7/1
N2 - The recent reduction of laser pulse duration down to the attosecond regime offers unprecedented opportunities to investigate ultrafast changes in the electron density before nuclear motion sets in. Here, we investigate the hole dynamics in the Caffeine molecule that is induced by an ionizing XUV pulse of 6 fs duration using the approximate time-dependent density functional theory method TD-DFTB. In order to account for ionization in a localized atomic orbital basis we apply a complex absorbing potential to model the continuum. Propagation of the time-dependent Kohn–Sham equations allows us to extract the time-dependent hole density taking the pulse shape explicitly into account. Results show that the sudden ionization picture, which is often used to motivate an uncorrelated initial state, fails for realistic pulses. We further find a strong dependence of the hole dynamics on the polarization of the laser field. Notwithstanding, we observe fs charge migration between two distant functional groups in Caffeine even after averaging over the molecular orientation.
AB - The recent reduction of laser pulse duration down to the attosecond regime offers unprecedented opportunities to investigate ultrafast changes in the electron density before nuclear motion sets in. Here, we investigate the hole dynamics in the Caffeine molecule that is induced by an ionizing XUV pulse of 6 fs duration using the approximate time-dependent density functional theory method TD-DFTB. In order to account for ionization in a localized atomic orbital basis we apply a complex absorbing potential to model the continuum. Propagation of the time-dependent Kohn–Sham equations allows us to extract the time-dependent hole density taking the pulse shape explicitly into account. Results show that the sudden ionization picture, which is often used to motivate an uncorrelated initial state, fails for realistic pulses. We further find a strong dependence of the hole dynamics on the polarization of the laser field. Notwithstanding, we observe fs charge migration between two distant functional groups in Caffeine even after averaging over the molecular orientation.
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U2 - 10.1140/epjb/e2018-90223-5
DO - 10.1140/epjb/e2018-90223-5
M3 - Article
AN - SCOPUS:85049530499
VL - 91
JO - Zeitschrift für Physik B Condensed Matter and Quanta
JF - Zeitschrift für Physik B Condensed Matter and Quanta
SN - 1434-6028
IS - 7
M1 - 152
ER -