A curious regularity in the dissociative photoionization of fluorinated benzenes: why do C6F6+ and C6H6+ dissociate so differently?

Kinugawa, Tohru; Hodgekins, A. M.; Eland, J.H.D.

doi:10.1016/s0009-2614(02)01859-6

Cited by 3 publications

(1 citation statement)

References 9 publications

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“…Not many studies have focused specifically on the effects of the replacement of one atom within a molecule. One such by Eland et al 8 concentrated on the fluorination effects in benzene and found that the probability of certain fragmentation pathways depends greatly on the degree of fluorination. Replacing hydrogen(s) with fluorine clearly has, due to their very different electronic properties, many consequences for the intramolecular charge distribution, bonding, and structure.…”

Section: ■ Introductionmentioning

confidence: 99%

Photofragmentation of Serine Following C 1s Core Ionization—Comparison with Cysteine

Itälä

Levola

et al. 2016

J. Phys. Chem. A

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Photofragmentation pathways of doubly ionized serine molecules are investigated and compared with those of cysteine. The main motivation for the study is to investigate if an atomic substitution within the same group of elements, namely replacing sulfur (in cysteine) with oxygen (in serine), causes a major change in the C 1s core ionization induced dissociation pattern in the molecules of otherwise identical structure. The results show that in serine there is a single completely dominant fragmentation channel producing the (CNH + 2−4 , COH + 1−3 ) pairs, whereas in cysteine there are also many other fragmentation channels. The employed experimental method was the photoelectron-photoion-photoion coincidence (PEPIPICO) technique 1 with synchrotron radiation tuned to ionize desired core levels. Molecular dynamics calculations were also carried out in order to extract information on the fragmentation and the neutral final fragments.

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Section: ■ Introductionmentioning

confidence: 99%

Photofragmentation of Serine Following C 1s Core Ionization—Comparison with Cysteine

Itälä

Levola

et al. 2016

J. Phys. Chem. A

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Ionized o-, m-, and p-difluorobenzene dissociate through ring-opened intermediates: A TPEPICO investigation

Boulanger

Holland

Shaw

et al. 2009

J. Am. Soc. Mass Spectrom.

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Threshold photoelectron photoion coincidence (TPEPICO) experiments have shown that o-, m-, and p-difluorobenzene ions dissociate via a common, ring-opened intermediate and not via ionized p-difluorobenzene. Rice-Ramsperger-Kassel-Marcus (RRKM) modeling of the experimental breakdown curves yields activation energies for the initial isomerization of 4.48 +/- 0.05, 4.55 +/- 0.05, and 4.68 +/- 0.05 eV for o-, m-, and p-difluorobenzene, respectively. These values place each ion at a similar absolute energy and thus similar transition states. A large positive DeltaS(double dagger) for each ion (ca 100 J K(-1) mol(-1)) suggests a ring-opened structure for these transition states.

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Data acquisition schemes for continuous two-particle time-of-flight coincidence experiments

Bodi¹,

Sztáray²,

Baer³

et al. 2007

Review of Scientific Instruments

164

171

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Three data acquisition schemes for two-particle coincidence experiments with a continuous source are discussed. The single-start/single-stop technique, implemented with a time-to-pulse-height converter, results in a complicated spectrum and breaks down severely at high count rates. The single-start/multiple-stop setup, based on a time-to-digital converter and the first choice in today's similar coincidence experiments, performs significantly better at high count rates, but its performance is still hampered if the time-of-flight range is large, and the false coincidence background is variable if the event frequency and the collection efficiency of the starts are both high. A straightforward, multistart/multistop setup is proposed for coincidence experiments. By collecting all detector data, it ensures the highest signal-to-noise ratio, constant background, and fast data acquisition and can now be easily constructed with commercially available time-to-digital converters. Analytical and numerically evaluated formulas are derived to characterize the performance of each setup in a variety of environments. Computer simulated spectra are presented to illustrate the analytically predicted features of the various raw time-of-flight distributions obtained with each technique.

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A curious regularity in the dissociative photoionization of fluorinated benzenes: why do C6F6+ and C6H6+ dissociate so differently?

Cited by 3 publications

References 9 publications

Photofragmentation of Serine Following C 1s Core Ionization—Comparison with Cysteine

Photofragmentation of Serine Following C 1s Core Ionization—Comparison with Cysteine

Ionized o-, m-, and p-difluorobenzene dissociate through ring-opened intermediates: A TPEPICO investigation

Data acquisition schemes for continuous two-particle time-of-flight coincidence experiments

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