title: Decoherence, control and attosecond probing of XUV-induced charge migration in biomolecules. A theoretical outlook.
abstract: The sudden ionization of a molecule by an attosecond pulse is followed by charge redistribution on a time scale from a few femtoseconds down to hundreds of attoseconds. This ultrafast redistribution is the result of the coherent superposition of electronic continua associated with the ionization thresholds that are reached by the broadband attosecond pulse. Thus, a correct theoretical description of the time evolution of the ensuing wave packet requires the knowledge of the actual ionization amplitudes associated with all open ionization channels, a real challenge for large and medium-size molecules. Recently, the first calculation of this kind has come to light, allowing for interpretation of ultrafast electron dynamics observed in attosecond pump-probe experiments performed on the amino acid phenylalanine [Calegari et al., Science 2014, 346, 336]. However, as in most previous theoretical works, the interpretation was based on various simplifying assumptions, namely, the ionized electron was not included in the description of the cation dynamics, the nuclei were fixed at their initial position during the hole migration process, and the effect of the IR probe pulse was ignored. Here we go a step further and discuss the consequences of including these effects in the photoionization of the glycine molecule. We show that (i) the ionized electron does not affect hole dynamics beyond the first femtosecond, and (ii) nuclear dynamics has only a significant effect after approximately 8 fs, but does not destroy the coherent motion of the electronic wave packet during at least few additional tens of fs. As a first step towards understanding the role of the probe pulse, we have considered an XUV probe pulse, instead of a strong IR one, and show that such an XUV probe does not introduce significant distortions in the pump-induced dynamics, suggesting that pump-probe strategies are suitable for imaging and manipulating charge migration in complex molecules. Furthermore, we show that hole dynamics can be changed by shaping the attosecond pump pulse, thus opening the door to the control of charge dynamics in biomolecules.
authors.affiliation: Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain. fernando.martin@uam.es.
authors.forename: Manuel
authors.initials: M
authors.lastname: Lara-Astiaso
authors.affiliation: Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain. fernando.martin@uam.es.
authors.forename: David
authors.initials: D
authors.lastname: Ayuso
authors.affiliation: IBM Research GmbH, Zurich Research Laboratory, 8803 Rueschlikon, Switzerland.
authors.forename: Ivano
authors.initials: I
authors.lastname: Tavernelli
authors.affiliation: Dipartimento di Scienze Chimiche e Farmaceutiche, Università di Trieste and CNR-Istituto Officina dei Materiali, 34127 Trieste, Italy.
authors.forename: Piero
authors.initials: P
authors.lastname: Decleva
authors.affiliation: Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain. fernando.martin@uam.es.
authors.forename: Alicia
authors.initials: A
authors.lastname: Palacios
authors.affiliation: Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain. fernando.martin@uam.es and Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nano), Campus Universitario de Cantoblanco, 28049 Madrid, Spain and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Martín
mesh_terms: D002412:Cations; D004583:Electrons; D005998:Glycine / Q000737:chemistry*
chemical_list: D002412:Cations; D005998:Glycine