Photoelectron spectra of Al2O2− and Al3O3−via slow electron velocity-map imaging

Isomer-specific, high-resolution photoelectron spectra of cryogenically-cooled pyridinide anions obtained using slow photoelectron velocity-map imaging are presented. New vibrational structure in the detachment spectrum of para-pyridinide is resolved, and the spectra of meta- and ortho-pyridinide are reported for the first time. These spectra yield electron affinities of 1.4797(5), 1.4473(5), and 0.8669(7) eV for the para-, meta- and ortho-pyridyl radicals, respectively, as well as a number of vibrational frequencies for each neutral isomer. While most of the resolved structure in all three spectra is readily assigned by comparison to B3LYP/6-311+G* Franck-Condon simulations, the para-pyridinide spectrum shows newly-resolved fine structure attributed to anharmonic coupling within the vibrational manifold of the corresponding neutral radical. Isomeric trends in the photoelectron angular distributions are rationalized by approximating the detached anion orbitals as superpositions of s, p, and d-like hydrogenic orbitals, based on an application of Sanov’s generalized mixing model [J. Chem. Phys. 141, 124312 (2014)]. The presented experimental and theoretical results are used to address the relative energies of the anion and neutral isomers, as well as the site-specific bond dissociation energies of pyridine.

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High-Resolution Photoelectron Spectroscopy of the Pyridinide Isomers

10.26434/chemrxiv.9105134.v1 ◽

2019 ◽

Author(s):

Jessalyn DeVine ◽

Mark C. Babin ◽

Katherine Blackford ◽

Daniel Neumark

Keyword(s):

High Resolution ◽

Photoelectron Spectroscopy ◽

Chem Phys ◽

Photoelectron Spectra ◽

Velocity Map Imaging ◽

Neutral Radical ◽

Dissociation Energies ◽

Anharmonic Coupling ◽

First Time ◽

Photoelectron Angular Distributions

Isomer-specific, high-resolution photoelectron spectra of cryogenically-cooled pyridinide anions obtained using slow photoelectron velocity-map imaging are presented. New vibrational structure in the detachment spectrum of para-pyridinide is resolved, and the spectra of meta- and ortho-pyridinide are reported for the first time. These spectra yield electron affinities of 1.4797(5), 1.4473(5), and 0.8669(7) eV for the para-, meta- and ortho-pyridyl radicals, respectively, as well as a number of vibrational frequencies for each neutral isomer. While most of the resolved structure in all three spectra is readily assigned by comparison to B3LYP/6-311+G* Franck-Condon simulations, the para-pyridinide spectrum shows newly-resolved fine structure attributed to anharmonic coupling within the vibrational manifold of the corresponding neutral radical. Isomeric trends in the photoelectron angular distributions are rationalized by approximating the detached anion orbitals as superpositions of s, p, and d-like hydrogenic orbitals, based on an application of Sanov’s generalized mixing model [J. Chem. Phys. 141, 124312 (2014)]. The presented experimental and theoretical results are used to address the relative energies of the anion and neutral isomers, as well as the site-specific bond dissociation energies of pyridine.

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High Resolution Photoelectron Spectroscopy of Cryogenically-Cooled NO3ˉ

10.26434/chemrxiv.9974699.v1 ◽

2019 ◽

Author(s):

Mark Babin ◽

Jessalyn DeVine ◽

John F. Stanton ◽

Daniel Neumark ◽

Martin DeWitt

Keyword(s):

High Resolution ◽

Photoelectron Spectroscopy ◽

Photoelectron Spectra ◽

Velocity Map Imaging ◽

Vibrational Assignment ◽

Neutral Radical ◽

Resolution Measurement ◽

Energy Dependent ◽

Franck Condon ◽

Insight Into

High-resolution anion photoelectron spectra of cryogenically cooled NO3ˉ anions obtained using slow photoelectron velocity-map imaging are presented and provide new insight into the vibronic structure of the corresponding neutral radical. A combination of improved spectral resolution, measurement of energy-dependent intensity effects, temperature control, and comparison to theory allows for full assignment of the vibronic features observed in this spectrum. We obtain a refined electron affinity of 3.9289(14) eV for NO3. Further, the appearance of Franck-Condon forbidden transitions from vibrationally cold anions to neutral states with excitation along the NO3 v4 mode confirms that these features arise from vibronic coupling with the excited state of NO3 and are not hot bands as has been suggested. Together, the suite of experimental and simulated results provides clear evidence that the v3 fundamental of NO3 resides near 1050 cm−1, addressing a long-standing controversy surrounding this vibrational assignment.

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High Resolution Photoelectron Spectroscopy of Cryogenically-Cooled NO3ˉ

10.26434/chemrxiv.9974699 ◽

2019 ◽

Author(s):

Mark Babin ◽

Jessalyn DeVine ◽

John F. Stanton ◽

Daniel Neumark ◽

Martin DeWitt

Keyword(s):

High Resolution ◽

Photoelectron Spectroscopy ◽

Photoelectron Spectra ◽

Velocity Map Imaging ◽

Vibrational Assignment ◽

Neutral Radical ◽

Resolution Measurement ◽

Energy Dependent ◽

Franck Condon ◽

Insight Into

High-resolution anion photoelectron spectra of cryogenically cooled NO3ˉ anions obtained using slow photoelectron velocity-map imaging are presented and provide new insight into the vibronic structure of the corresponding neutral radical. A combination of improved spectral resolution, measurement of energy-dependent intensity effects, temperature control, and comparison to theory allows for full assignment of the vibronic features observed in this spectrum. We obtain a refined electron affinity of 3.9289(14) eV for NO3. Further, the appearance of Franck-Condon forbidden transitions from vibrationally cold anions to neutral states with excitation along the NO3 v4 mode confirms that these features arise from vibronic coupling with the excited state of NO3 and are not hot bands as has been suggested. Together, the suite of experimental and simulated results provides clear evidence that the v3 fundamental of NO3 resides near 1050 cm−1, addressing a long-standing controversy surrounding this vibrational assignment.

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Slow Electron Velocity-Map Imaging of Negative Ions: Applications to Spectroscopy and Dynamics†

The Journal of Physical Chemistry A ◽

10.1021/jp807182q ◽

2008 ◽

Vol 112 (51) ◽

pp. 13287-13301 ◽

Cited By ~ 162

Author(s):

Daniel M. Neumark

Keyword(s):

Negative Ions ◽

Electron Velocity ◽

Velocity Map Imaging ◽

Slow Electron

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Low-lying vibronic level structure of the ground state of the methoxy radical: Slow electron velocity-map imaging (SEVI) spectra and Köppel-Domcke-Cederbaum (KDC) vibronic Hamiltonian calculations

The Journal of Chemical Physics ◽

10.1063/1.4984963 ◽

2017 ◽

Vol 146 (22) ◽

pp. 224309 ◽

Cited By ~ 8

Author(s):

Marissa L. Weichman ◽

Lan Cheng ◽

Jongjin B. Kim ◽

John F. Stanton ◽

Daniel M. Neumark

Keyword(s):

Ground State ◽

Level Structure ◽

Electron Velocity ◽

Velocity Map Imaging ◽

Slow Electron ◽

Methoxy Radical ◽

Vibronic Level

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Interference stabilization of autoionizing states in molecular N2 studied by time- and angular-resolved photoelectron spectroscopy

Faraday Discussions ◽

10.1039/c6fd00093b ◽

2016 ◽

Vol 194 ◽

pp. 509-524 ◽

Cited By ~ 6

Author(s):

Martin Eckstein ◽

Nicola Mayer ◽

Chung-Hsin Yang ◽

Giuseppe Sansone ◽

Marc J. J. Vrakking ◽

...

Keyword(s):

Decay Rate ◽

Photoelectron Spectroscopy ◽

Rydberg States ◽

Electronic States ◽

The Other ◽

Photoelectron Spectra ◽

Angular Distributions ◽

Velocity Map Imaging ◽

Imaging Spectrometer ◽

Exponential Decay Rate

An autoionizing resonance in molecular N2 is excited by an ultrashort XUV pulse and probed by a subsequent weak IR pulse, which ionizes the contributing Rydberg states. Time- and angular-resolved photoelectron spectra recorded with a velocity map imaging spectrometer reveal two electronic contributions with different angular distributions. One of them has an exponential decay rate of 20 ± 5 fs, while the other one is shorter than 10 fs. This observation is interpreted as a manifestation of interference stabilization involving the two overlapping discrete Rydberg states. A formalism of interference stabilization for molecular ionization is developed and applied to describe the autoionizing resonance. The results of calculations suggest, that the effect of the interference stabilization is facilitated by rotationally-induced couplings of electronic states with different symmetry.

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