Time-dependent theoretical description of molecular autoionization produced by femtosecond xuv laser pulses

Sanz-Vicario, José Luis; Bachau, H.; Martín, Fernando

doi:10.1103/physreva.73.033410

Cited by 98 publications

(127 citation statements)

References 39 publications

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“…[8] and [31] for more details). The method includes all electronic and vibrational (dissociative) degrees of freedom and therefore accounts for electron correlation and the nuclear motion.…”

Section: B Quantum Calculationsmentioning

confidence: 99%

Reconstruction of an excited-state molecular wave packet with attosecond transient absorption spectroscopy

et al. 2016

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Attosecond science promises to allow new forms of quantum control in which a broadband isolated attosecond pulse excites a molecular wave packet consisting of a coherent superposition of multiple excited electronic states. This electronic excitation triggers nuclear motion on the molecular manifold of potential energy surfaces and can result in permanent rearrangement of the constituent atoms. Here, we demonstrate attosecond transient absorption spectroscopy (ATAS) as a viable probe of the electronic and nuclear dynamics initiated in excited states of a neutral molecule by a broadband vacuum ultraviolet pulse. Owing to the high spectral and temporal resolution of ATAS, we are able to reconstruct the time evolution of a vibrational wave packet within the excited B 1 u + electronic state of H 2 via the laser-perturbed transient absorption spectrum.

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Section: B Quantum Calculationsmentioning

confidence: 99%

Reconstruction of an excited-state molecular wave packet with attosecond transient absorption spectroscopy

et al. 2016

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“…This time-independent theory along with Dill's formulas [2] have been used to compute MFPADs in H 2 and D 2 for linearly polarized light [27] as well as for circularly polarized light [23,39]. Here we use instead a recent extension of this methodology to the time domain [40], which allows for the temporal scrutiny of the resonant photodynamics involved in CDAD. The adiabatic and the dipolar approximations are assumed.…”

Section: Theoretical Methodsmentioning

confidence: 99%

“…The time-dependent wave function (r,R,t) is expanded in a basis of fully correlated adiabatic Born-Oppenheimer (BO) vibronic stationary states of energy W k , which include the bound states, the resonant doubly excited states, and the nonresonant continuum states of H 2 [40]:…”

Section: Theoretical Methodsmentioning

confidence: 99%

Circular dichroism in molecular-frame photoelectron angular distributions in the dissociative photoionization ofH2andD2molecules

et al. 2014

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The presence of net circular dichroism in the photoionization of nonchiral homonuclear molecules has been put in evidence recently through the measurement of molecular-frame photoelectron angular distributions in dissociative photoionization of H 2 [Dowek et al., Phys. Rev. Lett. 104, 233003 (2010)]. In this work we present a detailed study of circular dichroism in the photoelectron angular distributions of H 2 and D 2 molecules, oriented perpendicularly to the propagation vector of the circularly polarized light, at different photon energies (20, 27, and 32.5 eV). Circular dichroism in the angular distributions at 20 and to a large extent 27 eV exhibits the usual pattern in which inversion symmetry is preserved. In contrast, at 32.5 eV, the inversion symmetry breaks down, which eventually leads to total circular dichroism after integration over the polar emission angle. Time-dependent ab initio calculations support and explain the observed results for H 2 in terms of quantum interferences between direct photoionization and delayed autoionization from the Q 1 and Q 2 doubly excited states into ionic states (1sσ g and 2pσ u ) of different inversion symmetry. Nevertheless, for D 2 at 32.5 eV, there is a particular case where theory and experiment disagree in the magnitude of the symmetry breaking: when D + ions are produced with an energy of around 5 eV. This reflects the subleties associated to such simple molecules when exposed to this fine scrutiny.

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“…Numerical solutions seeking to include the vibrational motion have only been obtained by reducing the dimensionality of the problem [49,50]. Very recently, the full dimensionality of the electronic and vibrational problem has been taken into account by performing a close-coupling expansion of the time-dependent molecular wave function Φ(r, R, t) [51][52][53][54][55][56][57][58][59][60] (this is at variance with previous applications of the time-dependent close-coupling method within the fixed-nuclei approximation [61,62]). In this method, Φ(r, R, t) is expanded in the basis of stationary vibronic states Ψ nvn (r, R) of energy W nvn ,…”

Section: Time-dependent Theoriesmentioning

confidence: 99%

“…It is important to stress here that, in all existing applications of the time-dependent close-coupling method, non adiabatic couplings associated with the derivatives of the electronic wave functions with respect to the nuclear coordinates that arise upon substitution of expansion (10) in the TDSE are partially or totally neglected. In this context, and for practical reasons, it is most convenient to write the molecular stationary states Ψ lα εαvα (r, R) in the BO form given by equation (2) for autoionizing states provided that their coupling with the non resonant continuum states is also included (see [57] for details).…”

Section: Time-dependent Theoriesmentioning

confidence: 99%

Molecular ionization and dissociation using synchrotron radiation and ultrashort laser pulses

Martín¹

2007

J. Phys.: Conf. Ser.

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Abstract. An overview of recent theoretical progress to accurately describe non dissociative and dissociative ionization of molecules exposed to synchrotron radiation and ultrashort uv/xuv laser pulses is presented. The success of recent theoretical approaches rely on their ability to account for both the electronic and nuclear degrees of freedom. This is essential to describe the delicate interplay between the electronic motion and the molecule's vibration, especially in those cases where ionization occurs in a time scale comparable to that of the vibrational motion. Some of the most successful applications and the new physics that has emerged by comparing with recent kinematically complete experiments on H2 and D2 will be discussed. IntroductionMolecular ionization is one of the most elementary processes that occurs in the upper atmosphere [1] and in interstellar molecular clouds [2]. Since in molecules the absorbed energy is shared between electronic and nuclear degrees of freedom, the remaining molecular ion can be left in an excited vibrational or dissociative state. This is at variance with atomic ionization where the energy is entirely absorbed by the electrons. In early pictures of molecular ionization, the nuclear motion was either ignored or described in terms of the Franck-Condon (FC) approximation, in which electronic processes occurring at the equilibrium position of the nuclei are weighted by the squared overlap between the initial and final vibrational states. With the advent of kinematically complete experiments [3,4], in which the momenta of all charged particles is determined, new phenomena with an intrinsic molecular origin have been discovered (see, e.g., [5][6][7][8][9][10][11]). Also the above pictures have been revealed to be incomplete. In this manuscript, the important role of nuclear dynamics in molecular ionization produced by synchrotron radiation and ultrashort pulses will be demonstrated by means of recent ab initio theoretical calculations that account for all electronic and vibrational degrees of freedom.In particular, recent results for electron angular distributions from fixed-in-space molecules will be analyzed and compared with kinematically complete photoionization experiments using synchrotron radiation. These include double and single photoionization of H 2 (D 2 ). The range of excess photon energies considered goes from a few to several hundreds of eV. Also, multiphoton ionization of molecules by vuv ultrashort pulses will be discussed. In particular, the new physics that can be expected by varying pulse duration and intensity will be analyzed.

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Time-dependent theoretical description of molecular autoionization produced by femtosecond xuv laser pulses

Cited by 98 publications

References 39 publications

Reconstruction of an excited-state molecular wave packet with attosecond transient absorption spectroscopy

Reconstruction of an excited-state molecular wave packet with attosecond transient absorption spectroscopy

Circular dichroism in molecular-frame photoelectron angular distributions in the dissociative photoionization ofH2andD2molecules

Molecular ionization and dissociation using synchrotron radiation and ultrashort laser pulses

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