Photodissociation of Iso-Propoxy (I-C3H7O) Radical at 248 Nm

10.26434/chemrxiv.12268517 ◽

2020 ◽

Author(s):

Erin Sullivan ◽

Steven Saric ◽

Daniel Neumark

Keyword(s):

Electronic State ◽

Ground State ◽

Branching Ratio ◽

Ground Electronic State ◽

Angular Distributions ◽

Translational Energy ◽

Energy And Angular Distributions ◽

Three Body ◽

State Dissociation

Photodissociation of the i-C3H7O radical is investigated using fast beam photofragment translational spectroscopy. Neutral i-C3H7O radicals are produced through the photodetachment of a fast beam of i-C3H7O- anions and are subsequently dissociated using 248 nm (5.0 eV). The dominant product channels are CH3 + CH3CHO and OH + C3H6 with some contribution from H + C3H6O. CH3 and H loss are attributed to dissociation on the ground electronic state of i-C3H7O, but in a nonstatistical manner because RRKM dissociation rates exceed the rate of energy randomization. Translational energy and angular distributions for OH loss are consistent with ground state dissociation, but the branching ratio for this channel is considerably higher than predicted from RRKM rate calculations. These results corroborate what has been observed previously in C2H5O dissociation at 5.2 eV that yields CH3, H, and OH loss. Additionally, i-C3H7O undergoes three-body fragmentation to CH3 + CH3 + HCO and CH3 + CH4 + CO. These three-body channels are attributed to dissociation of i-C3H7O to CH3 + CH3CHO, followed by secondary dissociation of CH3CHO on its ground electronic state.

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Photodissociation Dynamics of the Methylsulfinyl Radical at 248 nm

10.26434/chemrxiv.7440743.v1 ◽

2018 ◽

Author(s):

Isaac Ramphal ◽

Chin Lee ◽

Daniel Neumark

Keyword(s):

Excited State ◽

Electronic State ◽

Ground State ◽

Molecular Beam ◽

Internal Conversion ◽

Ground Electronic State ◽

Electronically Excited ◽

State Dissociation ◽

Primary Channel

The photodissociation dynamics of jet-cooled methylsulfinyl radicals, CH3SO, at 248 nm have been investigated using molecular beam photofragment translational spectroscopy. The primary channel is CH3S + O, which occurs via the initially prepared excited CH3SO state by rapid cleavage of the S-O bond to produce ground state products. The minor SO + CH3 channel has two components in comparable proportions: a fast feature corresponding to rapid C-S cleavage on the excited state to produce CH3 and electronically excited SO, and a slow feature due to internal conversion of CH3SO followed by statistical dissociation on the ground electronic state. Statistical ground state dissociation also produces small amounts of CH2SO, likely sulfine, and H-atoms.

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Photodissociation Dynamics of the Methylsulfinyl Radical at 248 nm

10.26434/chemrxiv.7440743 ◽

2018 ◽

Author(s):

Isaac Ramphal ◽

Chin Lee ◽

Daniel Neumark

Keyword(s):

Excited State ◽

Electronic State ◽

Ground State ◽

Molecular Beam ◽

Internal Conversion ◽

Ground Electronic State ◽

Electronically Excited ◽

State Dissociation ◽

Primary Channel

The photodissociation dynamics of jet-cooled methylsulfinyl radicals, CH3SO, at 248 nm have been investigated using molecular beam photofragment translational spectroscopy. The primary channel is CH3S + O, which occurs via the initially prepared excited CH3SO state by rapid cleavage of the S-O bond to produce ground state products. The minor SO + CH3 channel has two components in comparable proportions: a fast feature corresponding to rapid C-S cleavage on the excited state to produce CH3 and electronically excited SO, and a slow feature due to internal conversion of CH3SO followed by statistical dissociation on the ground electronic state. Statistical ground state dissociation also produces small amounts of CH2SO, likely sulfine, and H-atoms.

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Quantum dynamics of the photostability of pyrazine

Physical Chemistry Chemical Physics ◽

10.1039/c5cp04605j ◽

2015 ◽

Vol 17 (44) ◽

pp. 29518-29530 ◽

Cited By ~ 16

Author(s):

Matthieu Sala ◽

Stéphane Guérin ◽

Fabien Gatti

Keyword(s):

Electronic State ◽

Ground State ◽

Quantum Dynamics ◽

Ground Electronic State ◽

Conical Intersection ◽

Radiationless Decay

We propose a new mechanism for the radiationless decay of photoexcited pyrazine to its ground electronic state involving a conical intersection between the dark Au(nπ) state and the ground state.

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A deep UV trigger for ground-state ring-opening dynamics of 1,3-cyclohexadiene

Science Advances ◽

10.1126/sciadv.aax6625 ◽

2019 ◽

Vol 5 (9) ◽

pp. eaax6625 ◽

Cited By ~ 5

Author(s):

Jennifer M. Ruddock ◽

Haiwang Yong ◽

Brian Stankus ◽

Wenpeng Du ◽

Nathan Goff ◽

...

Keyword(s):

Electronic State ◽

Ground State ◽

Ground Electronic State ◽

Source Analysis ◽

Time Resolved ◽

X Ray Scattering ◽

Linac Coherent Light Source ◽

Scattering Anisotropy ◽

Kinetics Of ◽

Single Bonds

We explore the photo-induced kinetics of 1,3-cyclohexadiene upon excitation at 200 nm to the 3p state by ultrafast time-resolved, gas-phase x-ray scattering using the Linac Coherent Light Source. Analysis of the scattering anisotropy reveals that the excitation leads to the 3px and 3py Rydberg electronic states, which relax to the ground state with a time constant of 208 ± 11 fs. In contrast to the well-studied 266 nm excitation, at 200 nm the majority of the molecules (76 ± 3%) relax to vibrationally hot cyclohexadiene in the ground electronic state. A subsequent reaction on the ground electronic state surface leads from the hot cyclohexadiene to 1,3,5-hexatriene, with rates for the forward and backward reactions of 174 ± 13 and 355 ± 45 ps, respectively. The scattering pattern of the final hexatriene product reveals a thermal distribution of rotamers about the carbon-carbon single bonds.

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A low-lying excited electronic state of the AlO molecule and the ground-state dissociation energy

Journal of Molecular Spectroscopy ◽

10.1016/0022-2852(69)90014-9 ◽

1969 ◽

Vol 32 (3) ◽

pp. 501-510 ◽

Cited By ~ 54

Author(s):

J.K. McDonald ◽

K.K. Innes

Keyword(s):

Electronic State ◽

Dissociation Energy ◽

Ground State ◽

Excited Electronic State ◽

State Dissociation ◽

Alo Molecule

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Determination of photofragment ion translational energy and angular distributions in an octopole ion guide: A case study of the Ar2+ and (N2O⋅H2O)+ cluster ions

The Journal of Chemical Physics ◽

10.1063/1.477367 ◽

1998 ◽

Vol 109 (17) ◽

pp. 7450-7461 ◽

Cited By ~ 13

Author(s):

S. Williams ◽

Y.-H. Chiu ◽

D. J. Levandier ◽

R. A. Dressler

Keyword(s):

Cluster Ions ◽

Angular Distributions ◽

Translational Energy ◽

Ion Guide ◽

Energy And Angular Distributions

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Electron‐impact dissociation of HCl: Translational energy and angular distributions of excited hydrogen atoms

The Journal of Chemical Physics ◽

10.1063/1.467554 ◽

1994 ◽

Vol 101 (5) ◽

pp. 3696-3703 ◽

Cited By ~ 4

Author(s):

Teiichiro Ogawa ◽

Toshiyuki Tsuboi ◽

Keiji Nakashima

Keyword(s):

Electron Impact ◽

Angular Distributions ◽

Translational Energy ◽

Hydrogen Atoms ◽

Electron Impact Dissociation ◽

Energy And Angular Distributions

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Translational energy and angular distributions of O() and O(j) fragments in the UV photodissociation of ozone

Chemical Physics ◽

10.1016/s0301-0104(97)00365-0 ◽

1998 ◽

Vol 231 (2-3) ◽

pp. 171-182 ◽

Cited By ~ 17

Author(s):

Kenshi Takahashi ◽

Nori Taniguchi ◽

Yutaka Matsumi ◽

Masahiro Kawasaki

Keyword(s):

Angular Distributions ◽

Translational Energy ◽

Energy And Angular Distributions

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Photodissociation Dynamics of the Tert-Butyl Perthiyl Radical

10.26434/chemrxiv.12217814.v1 ◽

2020 ◽

Author(s):

Bethan Nichols ◽

Erin Sullivan ◽

Daniel Neumark

Keyword(s):

Excited State ◽

Translational Energy ◽

Energy Distributions ◽

Dissociation Process ◽

The Third ◽

Available Energy ◽

Three Body ◽

A Minor ◽

193 Nm ◽

State Dissociation

The photodissociation dynamics of the tert-butyl perthiyl (t-BuSS) radical are investigated by fast-beam coincidence translational spectroscopy. A fast (6-8 keV) beam of neutral t-BuSS radicals is produced via photodetachment of the corresponding anion, followed by photodissociation at 248 nm (5.00 eV) or 193 nm (6.42 eV) and coincident detection of the neutral products. Photofragment mass and translational energy distributions are obtained at both wavelengths. At 248 nm, the dominant product channel (90%) is found to be S loss, with a product translational energy distribution that peaks close to the maximum available energy and an anisotropic photofragment angular distribution, indicating dissociation along a repulsive excited state. A minor channel (10%) leading to the formation of S2 + t-Bu is also observed. At 193 nm, both two- and three-body dissociation are observed. Formation of S2 + t-Bu is the dominant two-body product channel, with multiple electronic states of the S2 molecule produced via excited state dissociation processes. Formation of S + t-BuS is a minor two-body channel at this dissociation energy. The three-body channels are S2 + H + isobutene, S2 + CH3 + propene, and S + SH + isobutene. The first two of these channels result from a sequential dissociation process in which loss of S2 from t-BuSS results in ground state t-Bu with sufficient internal energy to undergo secondary fragmentation. The third three-body channel, S + SH + isobutene, is attributed to loss of internally excited HS2 from t-BuSS, which then rapidly dissociates to form S + SH in an asynchronous concerted dissociation process.

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