scholarly journals An experimental and computational study of the effect of aqueous solution on the multiphoton ionisation photoelectron spectrum of phenol

2020 ◽  
Vol 221 ◽  
pp. 202-218 ◽  
Author(s):  
Alice Henley ◽  
Jamie W. Riley ◽  
Bingxing Wang ◽  
Helen H. Fielding
Keyword(s):  
Aqueous Solution ◽  
Inelastic Scattering ◽  
Photoelectron Spectroscopy ◽  
Photoelectron Spectrum ◽  
Computational Study ◽  
Inhomogeneous Broadening ◽  
Solution Phase ◽  
Photoelectron Spectra ◽  
The Impact

We revisit the photoelectron spectroscopy of aqueous phenol in an effort to improve our understanding of the impact of inhomogeneous broadening and inelastic scattering on solution-phase photoelectron spectra.

scholarly journals Conformational behavior and electronic structure of silylketenes studied with quantum chemical calculations and photoelectron spectroscopy

1997 ◽  
Vol 75 (12) ◽  
pp. 1851-1861 ◽  
Author(s):  
Heidi M. Muchall ◽  
Nick H. Werstiuk ◽  
Jiangong Ma ◽  
Thomas T. Tidwell ◽  
Kuangsen Sung
Keyword(s):  
Electronic Structure ◽  
Quantum Chemical Calculations ◽  
Photoelectron Spectroscopy ◽  
Quantum Chemical ◽  
Computational Study ◽  
Photoelectron Spectra ◽  
Conformational Behavior ◽  
Torsional Angle ◽  
Orbital Interaction ◽  
Orbital Energies

The He(I) photoelectron spectra of silylketenes (Me3Si)2C=C=O (1), Me5Si2CH=C=O (2), Me2Si(CH=C=O)2 (3), MeSi(CH=C=O)3 (4), (SiMe2CH=C=O)2 (5), and (CH2SiMe2CH=C=O)2 (6) have been recorded and their structures and orbital energies have been calculated by ab initio methods. Orbital energies for disilanes 2 and 5 are strongly dependent on a Si-Si-C-C torsional angle due to σ–π orbital interaction. Comparisons between experimental and simulated spectra show that 2 and 5 prefer conformations in which the Si—Si bond and ketene group(s) are approximately orthogonal (113° and 111°, respectively). Silylalkenes Me5Si2CH=CH2 (7) and (SiMe2CH=CH2)2 (8), which have been included in the computational study, show the same behavior as their corresponding silylketenes. Silylbis- and trisketenes 3–6 do not exhibit π–π interaction of any significance. For Si—Si containing compounds, the best agreement between experimental and computed data was obtained when Becke3LYP/6-31G*//HF/3-21G* was employed. Keywords: conformational behavior, electronic structure, photoelectron spectroscopy, quantum chemical calculations, silylketenes.

scholarly journals Photoelectron spectroscopy of reactive intermediates

1988 ◽  
Vol 324 (1578) ◽  
pp. 197-207 ◽  
Keyword(s):  
Transition Metal ◽  
Gas Phase ◽  
Photoelectron Spectroscopy ◽  
Photoelectron Spectrum ◽  
Reactive Intermediates ◽  
Vapour Phase ◽  
Photoelectron Spectra ◽  
Triatomic Molecule ◽  
Recent Developments ◽  
Vanadium Monoxide

Recent developments in the use of photoelectron spectroscopy to study reactive intermediates in the gas phase are reviewed. The information to be derived on low-lying cationic states from such studies is illustrated by considering two diatomic molecules, NCI and PF, and one triatomic molecule, HNO. Also, the use of a transition-metal photoelectron spectrum to interpret the photoelectron spectrum of the corresponding transition-metal oxide is discussed by using the spectra of vanadium and vanadium monoxide as examples. The value of super-heating in high-temperature photoelectron spectroscopy is demonstrated by considering the vapour-phase photoelectron spectra of the monomers and dimers of sodium hydroxide.

Pyrolysis of 2-methoxy-5,5-dimethyl-2-methylthio- 2,5-dihydro[1,3,4]oxadiazole studied with photoelectron spectroscopy and DFT calculations — He(I) photoelectron spectrum of methoxy(methylthio)carbene

2006 ◽  
Vol 84 (4) ◽  
pp. 546-554 ◽  
Author(s):  
N H Werstiuk ◽  
A Klys ◽  
J Warkentin
Keyword(s):  
Heat Source ◽  
Dft Calculations ◽  
Key Words ◽  
Gas Phase ◽  
Photoelectron Spectroscopy ◽  
Photoelectron Spectrum ◽  
Calculated Data ◽  
Experimental Results ◽  
Photoelectron Spectra ◽  
Key Words 2

Gas-phase pyrolysis of 2-methoxy-2-methylsulfanyl-5,5-dimethyl-2,5-dihydro[1,3,4]oxadiazole (1) (also known as 2-methoxy-5,5-dimethyl-2-methylthio-2,5-dihydro[1,3,4]oxadiazole and 2-methoxy-2-methylthio-5,5-dimethyl-Δ3-l,3,4-oxadiazoline) in the source of an UV photoelectron spectrometer, by means of a CW CO2 laser as directed heat source, gave a photoelectron (PE) spectrum that included ionization bands belonging to acetone and methoxy(methylthio)carbene (3). Photoelectron spectra of authentic samples of (E)-1,2-dimethoxy-1,2-dimethyl thioethene (4), (Z)-1,2-dimethoxy-1,2-dimethylthioethene (5), S-methyl thioethanoate (6), and O-methyl ethanethioate (7), which can be derived by dimerization and rearrangement of the carbene, established that these compounds are not present in the pyrolysate. DFT calculations at the B3PW91/6-31+G(d,p) level and simulation of PE spectra at the B3LYP/6-31+G(d,p) level were instrumental in the interpretation of the experimental results. From the available experimental and calculated data, 3 is formed in a Sickle conformation upon pyrolysis of 1. Transition states for the rearrangement of 3 were examined with QTAIM. Key words: 2-methoxy-5,5-dimethyl-2-methylthio-2,5-dihydro[1,3,4]oxadiazole, pyrolysis, He(I) photoelectron spectroscopy, methoxy(methylthio)carbene, DFT calculations, QTAIM.

Rotationally resolved threshold photoelectron spectroscopy of O2 using coherent XUV: formation of vibrationally excited ions in the Franck–Condon gap

1994 ◽  
Vol 72 (11-12) ◽  
pp. 1284-1293 ◽  
Author(s):  
W. Kong ◽  
J. W. Hepburn
Keyword(s):  
Light Source ◽  
Photoelectron Spectroscopy ◽  
Photoelectron Spectrum ◽  
Extreme Ultraviolet ◽  
Photoelectron Spectra ◽  
Vibrationally Excited ◽  
Wide Range ◽  
Vibrational Levels ◽  
Franck Condon ◽  
Dissociative State

The rotationally resolved photoelectron spectrum of high vibrational levels of O2+ in the Franck–Condon gap was investigated using pulsed field ionization, zero kinetic energy photoelectron spectroscopy. By using a coherent extreme ultraviolet light source for single-photon excitation, the ν+ = 6–24 vibrational levels of O2+X2Πg were studied. This is the first time levels higher than ν+ = 14 have been observed with rotational resolution. The highest level studied in the present work had a vibrational energy corresponding to 70% of the well depth. Along with the novelty of the spectroscopic technique, the present results reveal interesting and new ionization dynamics. All levels observed are Franck–Condon forbidden, and are not observed in a conventional photoelectron spectrum. There was no direct relation between the vibrational bands and the autoionizing states observed in the photoionization efficiency spectrum in the same energy region, and the rotational line intensities observed in the various bands in the current threshold photoelectron spectra were all similar. The mechanism of this process was different from the "resonant autoionization" model, which involves coupling between a Rydberg state with a low principal quantum number, a dissociative state, arid the Rydberg series converging to the vibrationally excited ion states. Instead, the excitation process was believed to be more direct, involving mainly a dissociative state (or states) and the Rydberg states with a vibrationally excited ion core. Further investigation of this mechanism is still necessary, but the formation of these highly vibrationally excited ions opens a new horizon in state-selective reaction dynamics. With the coherent XUV light source and the PFI-ZEKE technique, a wide range of vibrational energies (up to 4 eV) can be deposited into the O2+ reactant with rovibrational selectivity.

2-Deoxyribose Radicals in the Gas Phase and Aqueous Solution. Transient Intermediates of Hydrogen Atom Abstraction from 2-Deoxyribofuranose

2005 ◽  
Vol 70 (11) ◽  
pp. 1769-1786 ◽  
Author(s):  
Luc A. Vannier ◽  
Chunxiang Yao ◽  
František Tureček
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Atom ◽  
Gas Phase ◽  
Computational Study ◽  
Hydrogen Atom Abstraction ◽  
Oh Radical ◽  
Free Energies ◽  
Intramolecular Hydrogen ◽  
Solvation Free Energies ◽  
Transient Intermediates

A computational study at correlated levels of theory is reported to address the structures and energetics of transient radicals produced by hydrogen atom abstraction from C-1, C-2, C-3, C-4, C-5, O-1, O-3, and O-5 positions in 2-deoxyribofuranose in the gas phase and in aqueous solution. In general, the carbon-centered radicals are found to be thermodynamically and kinetically more stable than the oxygen-centered ones. The most stable gas-phase radical, 2-deoxyribofuranos-5-yl (5), is produced by H-atom abstraction from C-5 and stabilized by an intramolecular hydrogen bond between the O-5 hydroxy group and O-1. The order of radical stabilities is altered in aqueous solution due to different solvation free energies. These prefer conformers that lack intramolecular hydrogen bonds and expose O-H bonds to the solvent. Carbon-centered deoxyribose radicals can undergo competitive dissociations by loss of H atoms, OH radical, or by ring cleavages that all require threshold dissociation or transition state energies >100 kJ mol-1. This points to largely non-specific dissociations of 2-deoxyribose radicals when produced by exothermic hydrogen atom abstraction from the saccharide molecule. Oxygen-centered 2-deoxyribose radicals show only marginal thermodynamic and kinetic stability and are expected to readily fragment upon formation.

scholarly journals Modification of Wood with Monoethanolamino-borate by The Data of X-Ray Photoelectron Spectroscopy

2018 ◽  
Vol 196 ◽  
pp. 04005
Author(s):  
Irina Stepina ◽  
Irina Kotlyarova
Keyword(s):  
Particle Size ◽  
Photoelectron Spectroscopy ◽  
Model Compound ◽  
Hydrolytic Stability ◽  
Photoelectron Spectra ◽  
Wood Cellulose ◽  
Rapid Loss ◽  
X Ray ◽  
Wood Protection ◽  
Cellulose Materials

The difficulty of wood protection from biocorrosion and fire is due to the fact that modifiers in use are washed out from the surface of the substrate under the influence of environmental factors. This results in a rapid loss of the protective effect and other practically important wood characteristics caused by the modification. To solve this problem is the aim of our work. Here, monoethanolaminoborate is used as a modifier, where electron-donating nitrogen atom provides a coordination number equal to four to a boron atom, which determines the hydrolytic stability of the compounds formed. Alpha-cellulose ground mechanically to a particle size of 1 mm at most was used as a model compound for the modification. X-ray photoelectron spectra were recorded on the XSAM-800 spectrometer (Kratos, UK). Prolonged extraction of the modified samples preceded the registration of the photoelectron spectra to exclude the fixation of the modifier molecules unreacted with cellulose. As a result of the experiment, boron and nitrogen atoms were found in the modified substrate, which indicated the hydrolytic stability of the bonds formed between the modifier molecules and the substrate. Therefore monoethanolaminoborate can be considered as a non-extractable modifier for wood-cellulose materials.

scholarly journals The Prisoners’ Dilemma in collaborative carriers’ request selection

2021 ◽  
Vol 29 (1) ◽  
pp. 73-87 ◽  
Author(s):  
Margaretha Gansterer ◽  
Richard F. Hartl
Keyword(s):  
Computational Study ◽  
Logistics Industry ◽  
Individual Outcomes ◽  
Selection Strategies ◽  
Prisoners Dilemma ◽  
Trading Mechanisms ◽  
And Behavior ◽  
The Impact ◽  
Idle Capacity

AbstractLogistics providers have to utilize available capacities efficiently in order to cope with increasing competition and desired quality of service. One possibility to reduce idle capacity is to build coalitions with other players on the market. While the willingness to enter such coalitions does exist in the logistics industry, the success of collaborations strongly depends on mutual trust and behavior of participants. Hence, a proper mechanism design, where carriers do not have incentives to deviate from jointly established rules, is needed. We propose to use a combinatorial auction system, for which several properties are already well researched but little is known about the auction’s first phase, where carriers have to decide on the set of requests offered to the auction. Profitable selection strategies, aiming at maximization of total collaboration gains, do exist. However, the impact on individual outcomes, if one or more players deviate from jointly agreed selection rules is yet to be researched. We analyze whether participants in an auction-based transport collaboration face a Prisoners’ Dilemma. While it is possible to construct such a setting, our computational study reveals that carriers do not profit from declining the cooperative strategy. This is an important and insightful finding, since it further strengthens the practical applicability of auction-based trading mechanisms in collaborative transportation.

scholarly journals Impact of high temperatures on aluminoceladonite studied by Mössbauer, Raman, X-ray diffraction and X-ray photoelectron spectroscopy

2021 ◽  
Author(s):  
Mariola Kądziołka-Gaweł ◽  
Maria Czaja ◽  
Mateusz Dulski ◽  
Tomasz Krzykawski ◽  
Magdalena Szubka
Keyword(s):  
Photoelectron Spectroscopy ◽  
Integral Intensity ◽  
Photoelectron Spectra ◽  
X Ray Diffraction ◽  
Structural Reorganization ◽  
Oh Groups ◽  
X Ray ◽  
Al Content ◽  
Integral Intensity Ratio ◽  
Higher Temperature

AbstractMössbauer, Raman, X-ray diffraction and X-ray photoelectron spectroscopies were used to examine the effects of temperature on the structure of two aluminoceladonite samples. The process of oxidation of Fe2+ to Fe3+ ions started at about 350 °C for the sample richer in Al and at 300 °C for the sample somewhat lower Al-content. Mössbauer results show that this process may be associated with dehydroxylation or even initiate it. The first stage of dehydroxylation takes place at a temperature > 350 °C when the adjacent OH groups are replaced with a single residual oxygen atom. Up to ~500 °C, Fe ions do not migrate from cis-octahedra to trans-octahedra sites, but the coordination number of polyhedra changes from six to five. This temperature can be treated as the second stage of dehydroxylation. The temperature dependence on the integral intensity ratio between bands centered at ~590 and 705 cm−1 (I590/I705) clearly reflects the temperature at which six-coordinated polyhedra are transformed into five-coordinated polyhedra. X-ray photoelectron spectra obtained in the region of the Si2p, Al2p, Fe2p, K2p and O1s core levels, highlighted a route to identify the position of Si, Al, K and Fe cations in a structure of layered silicates with temperature. All the measurements show that the sample with a higher aluminum content and a lower iron content in octahedral sites starts to undergo a structural reorganization at a relatively higher temperature than the less aluminum-rich sample does. This suggests that iron may perform an important role in the initiation of the dehydroxylation of aluminoceladonites.

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