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

2016 ◽  
Vol 194 ◽  
pp. 509-524 ◽  
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.

Photoelectron Angular Distributions Of Ultrathin NI/CU(001) Films

1996 ◽  
Vol 437 ◽  
Author(s):  
G.J. Mankey ◽  
K. Subramanian ◽  
R.L. Stockbauer ◽  
R.L. Kurtz
Keyword(s):  
Photoelectron Spectroscopy ◽  
Periodic Potential ◽  
Electronic States ◽  
Linear Dichroism ◽  
Angular Distributions ◽  
X Ray ◽  
Photoelectron Diffraction ◽  
Ellipsoidal Mirror ◽  
Magnetic Linear Dichroism ◽  
Photoelectron Angular Distributions

AbstractWe present measurements of the evolution with film thickness of the 3d electronic states at the Fermi energy of ultrathin Ni films. The morphology and thickness of the films is determined from x-ray photoelectron spectroscopy. x-ray photoelectron diffraction and x-ray magnetic linear dichroism using synchrotron radiation. Photoelectron angular distributions were measured using an ellipsoidal mirror analyzer. Even at submonolayer Ni coverages, the 3d electronic states exhibit bulk-like properties. This is attributed to the short screening length of electrons in metals, the localization of the 3d electrons, the similarity of the Ni and Cu ion cores, and finally the interaction with the underlying fcc periodic potential.

High-Resolution Photoelectron Spectroscopy of the Pyridinide Isomers

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.

Asymptotic analysis of solitons and double layers at the acoustic speed

2017 ◽  
Vol 83 (6) ◽  
Author(s):  
Carel P. Olivier ◽  
Frank Verheest ◽  
Shimul K. Maharaj
Keyword(s):  
Asymptotic Behaviour ◽  
Decay Rate ◽  
Double Layer ◽  
Taylor Series Expansion ◽  
The Other ◽  
Double Layers ◽  
Exponential Decay Rate ◽  
Layer Velocity ◽  
Acoustic Speed

In this paper, we consider the asymptotic behaviour of solitons and double layers. By using the Sagdeev pseudopotential formalism, a Taylor series expansion is used to derive the asymptotic behaviour. For solitons and supersolitons that propagate faster than the acoustic speed, an exponential decay rate is derived. In contrast, for acoustic speed solitons and supersolitons, we show that the decay rate is algebraic, resulting in much fatter tails. These results can be extended to double layers. However, the double layer velocity affects only one side of the tail. The other side of the tail is affected by the multiplicity of the double layer root. All the results are illustrated by means of a case study.

High-Resolution Photoelectron Spectroscopy of the Pyridinide Isomers

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.

High Resolution Photoelectron Spectroscopy of Cryogenically-Cooled NO3ˉ

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

<p></p><p>High-resolution anion photoelectron spectra of cryogenically cooled NO<sub>3</sub>ˉ 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 NO<sub>3</sub>. Further, the appearance of Franck-Condon forbidden transitions from vibrationally cold anions to neutral states with excitation along the NO<sub>3</sub> <i>v</i><sub>4</sub> mode confirms that these features arise from vibronic coupling with the excited state of NO<sub>3</sub> and are not hot bands as has been suggested. Together, the suite of experimental and simulated results provides clear evidence that the <i>v</i><sub>3</sub> fundamental of NO<sub>3</sub> resides near 1050 cm<sup>−1</sup>, addressing a long-standing controversy surrounding this vibrational assignment.</p> <p> </p><br><p></p>

High Resolution Photoelectron Spectroscopy of Cryogenically-Cooled NO3ˉ

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

<p></p><p>High-resolution anion photoelectron spectra of cryogenically cooled NO<sub>3</sub>ˉ 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 NO<sub>3</sub>. Further, the appearance of Franck-Condon forbidden transitions from vibrationally cold anions to neutral states with excitation along the NO<sub>3</sub> <i>v</i><sub>4</sub> mode confirms that these features arise from vibronic coupling with the excited state of NO<sub>3</sub> and are not hot bands as has been suggested. Together, the suite of experimental and simulated results provides clear evidence that the <i>v</i><sub>3</sub> fundamental of NO<sub>3</sub> resides near 1050 cm<sup>−1</sup>, addressing a long-standing controversy surrounding this vibrational assignment.</p> <p> </p><br><p></p>

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

2019 ◽  
Vol 217 ◽  
pp. 235-255 ◽  
Author(s):  
Jessalyn A. DeVine ◽  
Mark C. Babin ◽  
Daniel M. Neumark
Keyword(s):  
High Resolution ◽  
Aluminum Oxide ◽  
Photoelectron Spectroscopy ◽  
Photoelectron Spectra ◽  
Electron Velocity ◽  
Velocity Map Imaging ◽  
Slow Electron ◽  
Vibronic Structure

High-resolution photoelectron spectroscopy of cryogenically-cooled aluminum oxide anions shows new subtleties in the vibronic structure of Al2O2−/0 and Al3O3−/0.

Photoionization dynamics in CS fragmented from CS2 studied by high-resolution photoelectron spectroscopy

2004 ◽  
Vol 82 (6) ◽  
pp. 744-749
Author(s):  
Anouk M Rijs ◽  
Ellen HG Backus ◽  
Cornelis A de Lange
Keyword(s):  
High Resolution ◽  
Triplet State ◽  
Key Words ◽  
Excited States ◽  
Ground State ◽  
Photoelectron Spectroscopy ◽  
Electronic States ◽  
Reactive Intermediates ◽  
Photoelectron Spectra ◽  
Singlet Ground State

The photoionization dynamics of CS have been studied using high-resolution laser photoelectron spectroscopy. The photodissociation of CS2 at ~308 nm results in highly rotationally excited CS in its X1Σ+ singlet ground state, as well as in rotationally cold CS in the excited a3Π triplet state. The ground-state CS fragments are formed together with sulfur in its 3P, 1D, and 1S electronic states; triplet CS is produced in coincidence with ground-state sulfur (3P). In both channels the photoelectron spectra are dominated by Δv = 0 propensity, but transitions involving Δv = 1 and 2 are also observed. Key words: photoelectron spectroscopy, photoionization, photodissociation, excited states, reactive intermediates.

1212-Molybdo-Cuprates; effect of oxygenation in the structure, properties and electronic states

2014 ◽  
Vol 1655 ◽  
Author(s):  
Sourav Marik ◽  
A. J. Dos santos-Garcia ◽  
Christine Labrugere ◽  
Emilio Morán ◽  
Olivier Toulemonde ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Oxidation Reaction ◽  
Short Range ◽  
Magnetic Measurements ◽  
Electronic States ◽  
The Other ◽  
Superconducting Transition ◽  
X Ray ◽  
Flowing Oxygen ◽  
Structure Properties

ABSTRACTThe influence of oxygenation in the magnetism, superconductivity and electronic states for the Mo0.3Cu0.7Sr2RECu2Oy (RE = Y, Er and Tm) compounds are discussed here. The magnetic measurements on the as-prepared (AP) samples suggest the existence of short-range magnetic correlations due to the presence of the paramagnetic MoV cations in the copper chain site. On the other hand, all the oxygenated samples are not magnetic but superconducting. The high pressure oxygenated sample shows the highest superconducting transition temperature of TC = 84 K. The influence of oxygenation in the electronic states for the Mo0.3Cu0.7Sr2YCu2Oy system associated with an oxidation reaction leading from a non-superconducting to a superconducting state has also been investigated by means of X-ray photoelectron spectroscopy (XPS). XPS measurements show the predominance of the MoV oxidation state over the MoVI one in the AP material; annealing under flowing oxygen enhances both the MoVI and CuII amounts. A detailed study of the electronic states for the Mo0.3Cu0.7Sr2YCu2Oy samples has been performed and is also discussed.

scholarly journals The dicarbon bonding puzzle viewed with photoelectron imaging

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
B. A. Laws ◽  
S. T. Gibson ◽  
B. R. Lewis ◽  
R. W. Field
Keyword(s):  
Ground State ◽  
Bond Order ◽  
Electronic States ◽  
Photoelectron Spectra ◽  
Electron Detachment ◽  
Dominant Contribution ◽  
Photoelectron Imaging ◽  
Imaging Spectrometer ◽  
Highest Occupied Molecular Orbital ◽  
High Bond

AbstractBonding in the ground state of C$${}_{2}$$2 is still a matter of controversy, as reasonable arguments may be made for a dicarbon bond order of $$2$$2, $$3$$3, or $$4$$4. Here we report on photoelectron spectra of the C$${}_{2}^{-}$$2− anion, measured at a range of wavelengths using a high-resolution photoelectron imaging spectrometer, which reveal both the ground $${X}^{1}{\Sigma}_{\mathrm{g}}^{+}$$X1Σg+ and first-excited $${a}^{3}{\Pi}_{{\mathrm{u}}}$$a3Πu electronic states. These measurements yield electron angular anisotropies that identify the character of two orbitals: the diffuse detachment orbital of the anion and the highest occupied molecular orbital of the neutral. This work indicates that electron detachment occurs from predominantly $$s$$s-like ($$3{\sigma}_{\mathrm{g}}$$3σg) and $$p$$p-like ($$1{\pi }_{{\mathrm{u}}}$$1πu) orbitals, respectively, which is inconsistent with the predictions required for the high bond-order models of strongly $$sp$$sp-mixed orbitals. This result suggests that the dominant contribution to the dicarbon bonding involves a double-bonded configuration, with 2$$\pi$$π bonds and no accompanying $$\sigma$$σ bond.

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