Production of excited atomic hydrogen and deuterium from H<sub>2</sub>and D<sub>2</sub>photodissociation

Bozek, John D.; Furst, John; Gay, T. J.; Gould, Harvey; Kilcoyne, A. L. D.; Machacek, Joshua; Martín, Fernando; McLaughlin, K. W.; Sanz-Vicario, José Luis

doi:10.1088/0953-4075/39/23/006

Cited by 26 publications

(39 citation statements)

References 29 publications

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“…Other aspects include ion-pair formation [5], double photoionization [6], vibrational autoionization [7], rotational and vibrational structure in the photoelectron spectrum [8,9], resonant photoionization involving doubly excited states [10][11][12], and the photoelectron [13] and photoion [6,14] angular distributions. Other research includes a study of competition between photodissociation and photoionization [15], nonperturbative time-dependent calculations of ionization by femtosecond xuv laser pulses [16], strong-field infrared laser ionization [17], and symmetry breaking in dissociative photoionization [18]. Those processes can be understood and treated within the dipole approximation to the photon-electron interaction.…”

Section: Introductionmentioning

confidence: 99%

Dipole and nondipole photoionization of molecular hydrogen

et al. 2015

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We describe a theoretical approach to molecular photoionization that includes first-order corrections to the dipole approximation. The theoretical formalism is presented and applied to photoionization of H 2 over the 20-to 180-eV photon energy range. The angle-integrated cross section σ , the electric dipole anisotropy parameter β e , the molecular alignment anisotropy parameter β m , and the first-order nondipole asymmetry parameters γ and δ were calculated within the single-channel, static-exchange approximation. The calculated parameters are compared with previous measurements of σ and β m and the present measurements of β e and γ + 3δ. The dipole and nondipole angular distribution parameters were determined simultaneously using an efficient, multiangle measurement technique. Good overall agreement is observed between the magnitudes and spectral variations of the calculated and measured parameters. The nondipole asymmetries of He 1s and Ne 2p photoelectrons were also measured in the course of this work.

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Section: Introductionmentioning

confidence: 99%

Dipole and nondipole photoionization of molecular hydrogen

et al. 2015

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“…The structure of H 2 and the dynamics of its fragmentation channels are the subject of renewed studies both experimental, by synchrotron radiation or laser techniques or in ion beam experiment [15][16][17] via the study of dissociative recombination [18,19], and theoretical, by ab initio calculations or by the molecular multichannel quantum defect theory [20][21][22][23][24][25][26][27]. They are also part of the dynamics of H(2s) Bose Einstein Condensates [28].…”

Section: Epj Web Of Conferencesmentioning

confidence: 99%

Fast metastable hydrogen atoms from H₂molecules: twin atoms

Trimeche

Houdoux

Rahmat

et al. 2015

EPJ Web of Conferences

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Abstract. It is a difficult task to obtain "twin atoms", i.e. pairs of massive particles such that one can perform experiments in the same fashion that is routinely done with "twin photons". One possible route to obtain such pairs is by dissociating homonuclear diatomic molecules. We address this possibility by investigating the production of metastable H(2s) atoms coming from the dissociation of cold H 2 molecules produced in a Campargue nozzle beam crossing an electron beam from a high intensity pulsed electron gun. Dissociation by electron impact was chosen to avoid limitations of target molecular excited states due to selection rules. Detectors placed several centimeters away from the collision center, and aligned with respect to possible common molecular dissociation channel, analyze the neutral fragments as a function of their time-of-flight (TOF) through Lyman-detection. Evidence for the first time observed coincidence of pairs of H(2s) atoms obtained this way is presented.

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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%

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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Production of excited atomic hydrogen and deuterium from H₂and D₂photodissociation

Cited by 26 publications

References 29 publications

Dipole and nondipole photoionization of molecular hydrogen

Dipole and nondipole photoionization of molecular hydrogen

Fast metastable hydrogen atoms from H₂molecules: twin atoms

Molecular ionization and dissociation using synchrotron radiation and ultrashort laser pulses

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Production of excited atomic hydrogen and deuterium from H2and D2photodissociation

Cited by 26 publications

References 29 publications

Dipole and nondipole photoionization of molecular hydrogen

Dipole and nondipole photoionization of molecular hydrogen

Fast metastable hydrogen atoms from H2molecules: twin atoms

Molecular ionization and dissociation using synchrotron radiation and ultrashort laser pulses

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Product

Resources

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Production of excited atomic hydrogen and deuterium from H₂and D₂photodissociation

Fast metastable hydrogen atoms from H₂molecules: twin atoms