Vibration dependent branching and photoelectron angular distributions observed across the Cooper minimum region of bromobenzene

Vibrational state-resolved photoelectron anisotropy parameters, beta, for the ~X 2B1, ~B 2B2, and ~C2B1 state ionizations of bromobenzene have been recorded at photon energies ranging from 20.5 to 94 eV, so spanning the region of the expected bromine Cooper minimum (CM). The ~X state displays no CM...

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Main Authors: Powis, Ivan, Patanen, Minna, Antonsson, Egill, Nicolas, Christophe, Miron, Catalin, Holland, David M.P.
Format: Article
Language:English
Published: American Physical Society 2017
Online Access:https://eprints.nottingham.ac.uk/44252/
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author Powis, Ivan
Patanen, Minna
Antonsson, Egill
Nicolas, Christophe
Miron, Catalin
Holland, David M.P.
author_facet Powis, Ivan
Patanen, Minna
Antonsson, Egill
Nicolas, Christophe
Miron, Catalin
Holland, David M.P.
author_sort Powis, Ivan
building Nottingham Research Data Repository
collection Online Access
description Vibrational state-resolved photoelectron anisotropy parameters, beta, for the ~X 2B1, ~B 2B2, and ~C2B1 state ionizations of bromobenzene have been recorded at photon energies ranging from 20.5 to 94 eV, so spanning the region of the expected bromine Cooper minimum (CM). The ~X state displays no CM and its beta value is also independent of vibrational level, in accord with the Franck-Condon Approximation. The ~B and ~ C state beta values display the CM to differing degrees, but both show a vibrational dependence that extends well below the obvious CM dip. Calculations are presented that replicate these observations of Franck-Condon Approximation breakdown spanning an extended photon energy range. This is the first demonstration of such wide-ranging breakdown detected in the beta anisotropy parameter in the absence of any resonance. Measured and calculated vibrational branching ratios for these states are also presented. Although the ~B state branching ratios remain constant, in accord with Franck-Condon expectations, the ~X and (especially) the ~C state ratios display weak, quasi-linear variations across the studied range of photon energy, but with no apparent correlation with the CM position.
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spelling nottingham-442522020-05-08T09:45:19Z https://eprints.nottingham.ac.uk/44252/ Vibration dependent branching and photoelectron angular distributions observed across the Cooper minimum region of bromobenzene Powis, Ivan Patanen, Minna Antonsson, Egill Nicolas, Christophe Miron, Catalin Holland, David M.P. Vibrational state-resolved photoelectron anisotropy parameters, beta, for the ~X 2B1, ~B 2B2, and ~C2B1 state ionizations of bromobenzene have been recorded at photon energies ranging from 20.5 to 94 eV, so spanning the region of the expected bromine Cooper minimum (CM). The ~X state displays no CM and its beta value is also independent of vibrational level, in accord with the Franck-Condon Approximation. The ~B and ~ C state beta values display the CM to differing degrees, but both show a vibrational dependence that extends well below the obvious CM dip. Calculations are presented that replicate these observations of Franck-Condon Approximation breakdown spanning an extended photon energy range. This is the first demonstration of such wide-ranging breakdown detected in the beta anisotropy parameter in the absence of any resonance. Measured and calculated vibrational branching ratios for these states are also presented. Although the ~B state branching ratios remain constant, in accord with Franck-Condon expectations, the ~X and (especially) the ~C state ratios display weak, quasi-linear variations across the studied range of photon energy, but with no apparent correlation with the CM position. American Physical Society 2017-07-01 Article PeerReviewed application/pdf en https://eprints.nottingham.ac.uk/44252/1/IPowis%20Vibration%20Dependent%20Branching.pdf Powis, Ivan, Patanen, Minna, Antonsson, Egill, Nicolas, Christophe, Miron, Catalin and Holland, David M.P. (2017) Vibration dependent branching and photoelectron angular distributions observed across the Cooper minimum region of bromobenzene. Physical Review A, 96 (1). 013413. ISSN 1050-2947 https://link.aps.org/doi/10.1103/PhysRevA.96.013413 doi:10.1103/PhysRevA.96.013413 doi:10.1103/PhysRevA.96.013413
spellingShingle Powis, Ivan
Patanen, Minna
Antonsson, Egill
Nicolas, Christophe
Miron, Catalin
Holland, David M.P.
Vibration dependent branching and photoelectron angular distributions observed across the Cooper minimum region of bromobenzene
title Vibration dependent branching and photoelectron angular distributions observed across the Cooper minimum region of bromobenzene
title_full Vibration dependent branching and photoelectron angular distributions observed across the Cooper minimum region of bromobenzene
title_fullStr Vibration dependent branching and photoelectron angular distributions observed across the Cooper minimum region of bromobenzene
title_full_unstemmed Vibration dependent branching and photoelectron angular distributions observed across the Cooper minimum region of bromobenzene
title_short Vibration dependent branching and photoelectron angular distributions observed across the Cooper minimum region of bromobenzene
title_sort vibration dependent branching and photoelectron angular distributions observed across the cooper minimum region of bromobenzene
url https://eprints.nottingham.ac.uk/44252/
https://eprints.nottingham.ac.uk/44252/
https://eprints.nottingham.ac.uk/44252/