raphael marion - Academia.edu (original) (raw)

Papers by raphael marion

Research paper thumbnail of Non-adiabatic transitions in the near-UV photodissociation of H 3 +

Journal of Physics: Conference Series, 2020

Synopsis The near-UV photodissociation of H 3 + has been studied in a fast beam experiment. The k... more Synopsis The near-UV photodissociation of H 3 + has been studied in a fast beam experiment. The kinetic energy release and branching ratio among the fragmentation channels were obtained by three-dimensional imaging of the dissociation products. It is found that the photodissociation of vibrationally excited H 3 + mostly produces vibrationally cold H 2 + and hot H2. The non-adiabatic repopulation of the ground potential energy surface after excitation is accounted for by modelling the wavepacket dynamics on the intersecting potential energy surfaces.

Research paper thumbnail of Photodissociation as a probe of the H 3 + avoided crossing seam

Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2019

Experiments are conducted to investigate the role of the avoided crossing seam in the photodissoc... more Experiments are conducted to investigate the role of the avoided crossing seam in the photodissociation of H 3 + . Three-dimensional imaging of dissociation products is used to determine the kinetic energy release and branching ratio among the fragmentation channels. Vibrational distributions are measured by dissociative charge transfer of H 2 + products. It is found that the photodissociation of hot H 3 + in the near-ultraviolet produces cold H 2 + , but hot H 2 . Modelling the wavepacket dynamics along the repulsive potential energy surface accounts for the repopulation of the ground potential energy surface. The role of the avoided crossing seam is emphasized and its importance for the astrophysically relevant charge transfer reactions underlined. This article is part of a discussion meeting issue ‘Advances in hydrogen molecular ions: H 3 + , H 5 + and beyond’.

Research paper thumbnail of Total, partial and differential cross sections for the photodetachment of O$^-$

HAL (Le Centre pour la Communication Scientifique Directe), Apr 11, 2018

International audienc

Research paper thumbnail of Absolute total, partial, and differential cross sections for photodetachment of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mo>−</mml:mo></mml:msup></mml:math>

Physical review, Sep 17, 2018

Absolute total, partial, and differential cross sections for the photodetachment of the oxygen an... more Absolute total, partial, and differential cross sections for the photodetachment of the oxygen anion are reported for photon energies ranging from threshold (1.46 eV) to 5.5 eV. The total cross section was measured using the animated-crossed-beam technique while partial and differential cross sections were obtained using velocity map imaging. The measured values are in good agreement with theoretical results obtained from an R-matrix calculation using polarized pseudostates.

Research paper thumbnail of Autodetachment spectroscopy of metastable D2− and HD−

Physical Review A

This paper reports observations of the autodetachment spectrum of D 2 − and HD − , resolved in ro... more This paper reports observations of the autodetachment spectrum of D 2 − and HD − , resolved in rovibrational levels presenting lifetimes from 1 to 100 µs. The electronic kinetic-energy release was measured using the velocity-map imaging technique, enhanced by coincidence detection of the neutral species produced. The experimental results are compared with theoretical description of the ab initio-based nonlocal resonance model, confirming the main features predicted by theory while resolving the apparent discrepancy between spontaneous dissociation and detachment experiments by revealing the presence of an additional rovibrational level in D 2 − not predicted to be sufficiently long-lived by theory.

Research paper thumbnail of Absolute cross sections and asymmetry parameters for photodetachment of C−(4So)

Physical Review A

Absolute total cross sections and asymmetry parameters for the photodetachment of the 4 S o groun... more Absolute total cross sections and asymmetry parameters for the photodetachment of the 4 S o ground state of C − are reported for photon energies ranging from threshold to 6 eV. The total cross sections were measured using the Animated Crossed Beam technique incorporating corrections for saturation, while the asymmetry parameters were obtained using Velocity Map Imaging spectrometry. The measured values are in good agreement with theoretical results obtained from an R-matrix calculation using polarized pseudostates.

Research paper thumbnail of Photodetachment of C− in the ground state

Journal of Physics: Conference Series, 2020

Synopsis Absolute total cross sections and asymmetry parameters for photodetachment of C− (4So) h... more Synopsis Absolute total cross sections and asymmetry parameters for photodetachment of C− (4So) have been measured using animated-crossed-beam and velocity map imaging techniques, for photon energies from threshold up to 6eV. The cross sections are 15% to 25% larger than earlier experimental results above 2.2 eV. They are in very good agreement with those from a new R-matrix calculation using polarized pseudostates.

Research paper thumbnail of Autodetachment spectroscopy of the metastable HD− and D2− anions

Journal of Physics: Conference Series, 2020

Synopsis The autodetachment spectrum of decaying HD− and D 2 − has been recorded with a velocity-... more Synopsis The autodetachment spectrum of decaying HD− and D 2 − has been recorded with a velocity-map imaging spectrometer. Coincident detection of the neutral molecule permits the selection of events occuring in the center of the spectrometer. The discrete features of the spectrum are assigned to transitions between well identified ro-vibrational levels. Energies, lifetimes and branching ratios predicted with the non-local potential framework developed for associative detachment satisfactorily reproduce the experimental results.

Research paper thumbnail of A Third Luminous Shark Family: Confirmation of Luminescence Ability forZameus squamulosus(Squaliformes; Somniosidae)

Photochemistry and Photobiology, 2021

Since recently, shark’s bioluminescence has been recorded from two Squaliformes families, the Etm... more Since recently, shark’s bioluminescence has been recorded from two Squaliformes families, the Etmopteridae and Dalatiidae. Pictures of luminescence, light organ morphologies and physiology of the luminous control have been described for species of the Etmopteridae and Dalatiidae families. In 2015, a third luminous family, Somniosidae, was assumed to present a bioluminescent species, Zameus squamulosus. Up to now, confirmation of the luminous abilities of Z. squamulosus is lacking. Here, the luminescence of Z. squamulosus was in vivo recorded for the first time confirming the bioluminescence status of the third luminescent shark family. Additionally, photophore histology revealed the conservation of the light organ morphology across the luminous Squaliformes. Light transmittance analysis through the placoid scale added information on the luminescence efficiency and highlighted a new type of bioluminescent‐like squamation. All these data reinforced the likelihood that the common ancestor of Dalatiidae, Etmopteridae and Somniosidae may already have been luminescent for counterillumination purpose.

Research paper thumbnail of Non-adiabatic transitions in the near-UV photodissociation of H 3 +

Journal of Physics: Conference Series, 2020

Synopsis The near-UV photodissociation of H 3 + has been studied in a fast beam experiment. The k... more Synopsis The near-UV photodissociation of H 3 + has been studied in a fast beam experiment. The kinetic energy release and branching ratio among the fragmentation channels were obtained by three-dimensional imaging of the dissociation products. It is found that the photodissociation of vibrationally excited H 3 + mostly produces vibrationally cold H 2 + and hot H2. The non-adiabatic repopulation of the ground potential energy surface after excitation is accounted for by modelling the wavepacket dynamics on the intersecting potential energy surfaces.

Research paper thumbnail of Photodissociation as a probe of the H 3 + avoided crossing seam

Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2019

Experiments are conducted to investigate the role of the avoided crossing seam in the photodissoc... more Experiments are conducted to investigate the role of the avoided crossing seam in the photodissociation of H 3 + . Three-dimensional imaging of dissociation products is used to determine the kinetic energy release and branching ratio among the fragmentation channels. Vibrational distributions are measured by dissociative charge transfer of H 2 + products. It is found that the photodissociation of hot H 3 + in the near-ultraviolet produces cold H 2 + , but hot H 2 . Modelling the wavepacket dynamics along the repulsive potential energy surface accounts for the repopulation of the ground potential energy surface. The role of the avoided crossing seam is emphasized and its importance for the astrophysically relevant charge transfer reactions underlined. This article is part of a discussion meeting issue ‘Advances in hydrogen molecular ions: H 3 + , H 5 + and beyond’.

Research paper thumbnail of Total, partial and differential cross sections for the photodetachment of O$^-$

HAL (Le Centre pour la Communication Scientifique Directe), Apr 11, 2018

International audienc

Research paper thumbnail of Absolute total, partial, and differential cross sections for photodetachment of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mo>−</mml:mo></mml:msup></mml:math>

Physical review, Sep 17, 2018

Absolute total, partial, and differential cross sections for the photodetachment of the oxygen an... more Absolute total, partial, and differential cross sections for the photodetachment of the oxygen anion are reported for photon energies ranging from threshold (1.46 eV) to 5.5 eV. The total cross section was measured using the animated-crossed-beam technique while partial and differential cross sections were obtained using velocity map imaging. The measured values are in good agreement with theoretical results obtained from an R-matrix calculation using polarized pseudostates.

Research paper thumbnail of Autodetachment spectroscopy of metastable D2− and HD−

Physical Review A

This paper reports observations of the autodetachment spectrum of D 2 − and HD − , resolved in ro... more This paper reports observations of the autodetachment spectrum of D 2 − and HD − , resolved in rovibrational levels presenting lifetimes from 1 to 100 µs. The electronic kinetic-energy release was measured using the velocity-map imaging technique, enhanced by coincidence detection of the neutral species produced. The experimental results are compared with theoretical description of the ab initio-based nonlocal resonance model, confirming the main features predicted by theory while resolving the apparent discrepancy between spontaneous dissociation and detachment experiments by revealing the presence of an additional rovibrational level in D 2 − not predicted to be sufficiently long-lived by theory.

Research paper thumbnail of Absolute cross sections and asymmetry parameters for photodetachment of C−(4So)

Physical Review A

Absolute total cross sections and asymmetry parameters for the photodetachment of the 4 S o groun... more Absolute total cross sections and asymmetry parameters for the photodetachment of the 4 S o ground state of C − are reported for photon energies ranging from threshold to 6 eV. The total cross sections were measured using the Animated Crossed Beam technique incorporating corrections for saturation, while the asymmetry parameters were obtained using Velocity Map Imaging spectrometry. The measured values are in good agreement with theoretical results obtained from an R-matrix calculation using polarized pseudostates.

Research paper thumbnail of Photodetachment of C− in the ground state

Journal of Physics: Conference Series, 2020

Synopsis Absolute total cross sections and asymmetry parameters for photodetachment of C− (4So) h... more Synopsis Absolute total cross sections and asymmetry parameters for photodetachment of C− (4So) have been measured using animated-crossed-beam and velocity map imaging techniques, for photon energies from threshold up to 6eV. The cross sections are 15% to 25% larger than earlier experimental results above 2.2 eV. They are in very good agreement with those from a new R-matrix calculation using polarized pseudostates.

Research paper thumbnail of Autodetachment spectroscopy of the metastable HD− and D2− anions

Journal of Physics: Conference Series, 2020

Synopsis The autodetachment spectrum of decaying HD− and D 2 − has been recorded with a velocity-... more Synopsis The autodetachment spectrum of decaying HD− and D 2 − has been recorded with a velocity-map imaging spectrometer. Coincident detection of the neutral molecule permits the selection of events occuring in the center of the spectrometer. The discrete features of the spectrum are assigned to transitions between well identified ro-vibrational levels. Energies, lifetimes and branching ratios predicted with the non-local potential framework developed for associative detachment satisfactorily reproduce the experimental results.

Research paper thumbnail of A Third Luminous Shark Family: Confirmation of Luminescence Ability forZameus squamulosus(Squaliformes; Somniosidae)

Photochemistry and Photobiology, 2021

Since recently, shark’s bioluminescence has been recorded from two Squaliformes families, the Etm... more Since recently, shark’s bioluminescence has been recorded from two Squaliformes families, the Etmopteridae and Dalatiidae. Pictures of luminescence, light organ morphologies and physiology of the luminous control have been described for species of the Etmopteridae and Dalatiidae families. In 2015, a third luminous family, Somniosidae, was assumed to present a bioluminescent species, Zameus squamulosus. Up to now, confirmation of the luminous abilities of Z. squamulosus is lacking. Here, the luminescence of Z. squamulosus was in vivo recorded for the first time confirming the bioluminescence status of the third luminescent shark family. Additionally, photophore histology revealed the conservation of the light organ morphology across the luminous Squaliformes. Light transmittance analysis through the placoid scale added information on the luminescence efficiency and highlighted a new type of bioluminescent‐like squamation. All these data reinforced the likelihood that the common ancestor of Dalatiidae, Etmopteridae and Somniosidae may already have been luminescent for counterillumination purpose.