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

1998 ◽  
Vol 109 (17) ◽  
pp. 7450-7461 ◽  
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

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

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

<p>Photodissociation of the <i>i</i>-C<sub>3</sub>H<sub>7</sub>O radical is investigated using fast beam photofragment translational spectroscopy. Neutral <i>i</i>-C<sub>3</sub>H<sub>7</sub>O radicals are produced through the photodetachment of a fast beam of <i>i</i>-C<sub>3</sub>H<sub>7</sub>O<sup>-</sup> anions and are subsequently dissociated using 248 nm (5.0 eV). The dominant product channels are CH<sub>3</sub> + CH<sub>3</sub>CHO and OH + C<sub>3</sub>H<sub>6</sub> with some contribution from H + C<sub>3</sub>H<sub>6</sub>O. CH<sub>3</sub> and H loss are attributed to dissociation on the ground electronic state of <i>i</i>-C<sub>3</sub>H<sub>7</sub>O, 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 C<sub>2</sub>H<sub>5</sub>O dissociation at 5.2 eV that yields CH<sub>3</sub>, H, and OH loss. Additionally, <i>i</i>-C<sub>3</sub>H<sub>7</sub>O undergoes three-body fragmentation to CH<sub>3</sub> + CH<sub>3</sub> + HCO and CH<sub>3</sub> + CH<sub>4</sub> + CO. These three-body channels are attributed to dissociation of <i>i</i>-C<sub>3</sub>H<sub>7</sub>O to CH<sub>3</sub> + CH<sub>3</sub>CHO, followed by secondary dissociation of CH<sub>3</sub>CHO on its ground electronic state.</p>

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

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

<p>Photodissociation of the <i>i</i>-C<sub>3</sub>H<sub>7</sub>O radical is investigated using fast beam photofragment translational spectroscopy. Neutral <i>i</i>-C<sub>3</sub>H<sub>7</sub>O radicals are produced through the photodetachment of a fast beam of <i>i</i>-C<sub>3</sub>H<sub>7</sub>O<sup>-</sup> anions and are subsequently dissociated using 248 nm (5.0 eV). The dominant product channels are CH<sub>3</sub> + CH<sub>3</sub>CHO and OH + C<sub>3</sub>H<sub>6</sub> with some contribution from H + C<sub>3</sub>H<sub>6</sub>O. CH<sub>3</sub> and H loss are attributed to dissociation on the ground electronic state of <i>i</i>-C<sub>3</sub>H<sub>7</sub>O, 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 C<sub>2</sub>H<sub>5</sub>O dissociation at 5.2 eV that yields CH<sub>3</sub>, H, and OH loss. Additionally, <i>i</i>-C<sub>3</sub>H<sub>7</sub>O undergoes three-body fragmentation to CH<sub>3</sub> + CH<sub>3</sub> + HCO and CH<sub>3</sub> + CH<sub>4</sub> + CO. These three-body channels are attributed to dissociation of <i>i</i>-C<sub>3</sub>H<sub>7</sub>O to CH<sub>3</sub> + CH<sub>3</sub>CHO, followed by secondary dissociation of CH<sub>3</sub>CHO on its ground electronic state.</p>

scholarly journals Photodissociation Dynamics of Arn+ Cluster Ions

1994 ◽  
Vol 14 (1-3) ◽  
pp. 15-29 ◽  
Author(s):  
Takashi Nagata
Keyword(s):  
Kinetic Energy ◽  
Energy Release ◽  
Simulation Analysis ◽  
Kinetic Energy Release ◽  
Cluster Ions ◽  
Angular Distributions ◽  
High Kinetic Energy ◽  
Spectral Profiles ◽  
Direct Dissociation ◽  
Energy And Angular Distributions

The time-of-flight (TOF) spectra of Ar+ and Ar fragments produced in the photodissociation of Arn+ (3 ≦ n ≧ 24) were measured at wavelength around 540 nm. The kinetic-energy and angular distributions of the neutral photofragments were obtained for n = 3, 9 and 24 by a simulation analysis of the measured TOF spectral profiles. The overall aspect of the photodissociation process of Arn+ is deduced from these distributions within the context of trimer ion core model; a linear Ar3+ core is solvated by neutral Ar atoms. For Arn+ with 4 ≦ n ≲ 14, direct dissociation of the Ar3+ chromophoric core gives rise to Ar+ and/or Ar fragments with a high kinetic energy release. For the larger Arn+ (n ≳ 14), the production of high-kinetic-energy fragments is suppressed; “evaporation” of the solvent Ar atoms is instead the dominant channel of photofragmentation.

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

1998 ◽  
Vol 231 (2-3) ◽  
pp. 171-182 ◽  
Author(s):  
Kenshi Takahashi ◽  
Nori Taniguchi ◽  
Yutaka Matsumi ◽  
Masahiro Kawasaki
Keyword(s):  
Angular Distributions ◽  
Translational Energy ◽  
Energy And Angular Distributions

scholarly journals Photodissociation Mechanisms of Benzene Cluster Ions on the Excitation With hv = 0.5-3.0 eV

1995 ◽  
Vol 15 (2-4) ◽  
pp. 93-111 ◽  
Author(s):  
Kazuhiko Ohashi ◽  
Yasuhiro Nakai ◽  
Nobuyuki Nishi
Keyword(s):  
Photon Energy ◽  
Upper Bound ◽  
Bound State ◽  
Cluster Ions ◽  
Angular Distributions ◽  
Translational Energy ◽  
Neutral Cluster ◽  
Available Energy ◽  
Dissociative State

The photodissociation of mass-selected benzene cluster ions, (C6H6)n+(n=2−8), is studied to elucidate the dynamics of dissociation and the mechanism of fragmentation. For (C6H6)2+, the average translational energy and the angular distributions of the photofragments are measured as a function of photon energy (hv). The photoexcitation to an upper bound state with hv = 2.81 eV results in statistical energy disposal. Regardless of the excitation to a dissociative state with hv = 1.17-1.62 eV, only a small fraction (at most 10%) of the available energy is partitioned into the translation. For (C6H6)n+ with n = 5-8, the average number of neutral molecules ejected following photoexcitation increases linearly with increasing hv until (C6H6)2+ is reached as the product. The result suggests that the photofragmentation proceeds via the sequential evaporation of neutral monomers rather than the direct ejection of a neutral cluster.

A novel method for the determination of linting propensity of paper

TAPPI Journal ◽  
2012 ◽  
Vol 11 (10) ◽  
pp. 9-17
Author(s):  
ALESSANDRA GERLI ◽  
LEENDERT C. EIGENBROOD
Keyword(s):  
Ash Content ◽  
The Novel ◽  
Offset Printing ◽  
Excellent Correlation ◽  
End Conditions ◽  
Bottom Side ◽  
Novel Method ◽  
Total Fraction

A novel method was developed for the determination of linting propensity of paper based on printing with an IGT printability tester and image analysis of the printed strips. On average, the total fraction of the surface removed as lint during printing is 0.01%-0.1%. This value is lower than those reported in most laboratory printing tests, and more representative of commercial offset printing applications. Newsprint paper produced on a roll/blade former machine was evaluated for linting propensity using the novel method and also printed on a commercial coldset offset press. Laboratory and commercial printing results matched well, showing that linting was higher for the bottom side of paper than for the top side, and that linting could be reduced on both sides by application of a dry-strength additive. In a second case study, varying wet-end conditions were used on a hybrid former machine to produce four paper reels, with the goal of matching the low linting propensity of the paper produced on a machine with gap former configuration. We found that the retention program, by improving fiber fines retention, substantially reduced the linting propensity of the paper produced on the hybrid former machine. The papers were also printed on a commercial coldset offset press. An excellent correlation was found between the total lint area removed from the bottom side of the paper samples during laboratory printing and lint collected on halftone areas of the first upper printing unit after 45000 copies. Finally, the method was applied to determine the linting propensity of highly filled supercalendered paper produced on a hybrid former machine. In this case, the linting propensity of the bottom side of paper correlated with its ash content.

The Calculation of Turbulent Diffusion Coefficients in Aquatic Ecosystems

2019 ◽  
Vol 70 (11) ◽  
pp. 3903-3907
Author(s):  
Galina Marusic ◽  
Valeriu Panaitescu
Keyword(s):  
Transport Equation ◽  
Turbulent Diffusion ◽  
Diffusion Coefficients ◽  
Aquatic Ecosystems ◽  
Specific Area ◽  
Left Bank ◽  
The Right ◽  
Prut River

The paper deals with the issues related to the pollution of aquatic ecosystems. The influence of turbulence on the transport and dispersion of pollutants in the mentioned systems, as well as the calculation of the turbulent diffusion coefficients are studied. A case study on the determination of turbulent diffusion coefficients for some sectors of the Prut River is presented. A new method is proposed for the determination of the turbulent diffusion coefficients in the pollutant transport equation for specific sectors of a river, according to the associated number of P�clet, calculated for each specific area: the left bank, the right bank and the middle of the river.

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