Molecular frame photoelectron angular distributions in dissociative photoionization of H2in the region of the Q1and Q2doubly excited states

Lafosse, A.; Lebech, M.; Brenot, J. C.; Guyon, P. M.; Spielberger, L.; Jagutzki, O.; Houver, J. C.; Dowek, D.

doi:10.1088/0953-4075/36/23/007

Cited by 63 publications

(61 citation statements)

References 48 publications

(56 reference statements)

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“…This orbital approximation also enables one to predict, in this case, that the angular distribution of the photoelectrons should be very similar to that expected following photoionization out of an s orbital of an atom. This prediction was also confirmed by a measurement of the angular distribution of the photoelectrons following the ionization of H 2 with VUV radiation (Lafosse et al 2003).…”

Section: Rovibronic Photoionization Selection Rules and Intensity Dissupporting

confidence: 55%

High‐resolution Photoelectron Spectroscopy

Merkt

Willitsch

Hollenstein

2011

Handbook of High‐resolution Spectroscopy

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The evolution of photoelectron spectroscopy of neutral molecules in the gas phase, from its first applications in the early 1960s to the present day, is reviewed with emphasis on the description of methods that have contributed to the improvement of resolution. In the early days, photoelectron spectroscopy was very successfully used to study the electronic structure of molecules. As the resolution improved, the emphasis gradually shifted to studies of the structure and dynamics of molecular cations. Current methods enable one to fully resolve the rotational structure in the photoelectron spectra of polyatomic molecules and even to measure the fine and hyperfine structures of positively charged atoms and small molecules. Several of the methods providing high resolution make use of the long lifetimes and electric‐field‐ionization properties of high Rydberg states and give access to detailed information on molecular ionization channels and molecular photoionization.

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Section: Rovibronic Photoionization Selection Rules and Intensity Dissupporting

confidence: 55%

High‐resolution Photoelectron Spectroscopy

Merkt

Willitsch

Hollenstein

2011

Handbook of High‐resolution Spectroscopy

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“…In a very recent work [11], it has been clearly demonstrated that such interference effects cause symmetry breaking in dissociative photoionization. A first observation of asymmetric photoelectron emission from H 2 has been reported in pioneering experiments by Lafosse et al [81]. In a different context, asymmetric electron emission has also been observed in O 2 [82] as the result of the decay of atomic oxygen following photodissociation of the O 2 molecule.…”

Section: Photoionization Of H 2 Through Autoionizing Statesmentioning

confidence: 85%

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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“…This probability distribution is represented as a function of the electron energy and the photoion kinetic energy. A detailed analysis of the events in these KECDs for H 2 and D 2 DPI has been discussed elsewhere [44,46]. By integrating the KECDs over the electron energy one obtains the DPI cross section as a function of the photoion KE.…”

Section: 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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Molecular frame photoelectron angular distributions in dissociative photoionization of H₂in the region of the Q₁and Q₂doubly excited states

Cited by 63 publications

References 48 publications

High‐resolution Photoelectron Spectroscopy

High‐resolution Photoelectron Spectroscopy

Molecular ionization and dissociation using synchrotron radiation and ultrashort laser pulses

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

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