Intracluster Polymerization Reactions of Alkene Cluster Ions

Zhong, Qun; Poth, L.; Shi, Z.; Ford, and J. V.; Castleman, A. W.

doi:10.1021/jp963902o

Cited by 25 publications

(26 citation statements)

References 53 publications

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“…We conclude that ethyl radical is the product of an ion−molecule reaction, the nature of which is still speculative. In the gas-phase, ion−molecule reactions proceed via cluster ion intermediates, (C 2 H 4 ) n •+ , and product ions are observed with two, three, and four carbons. , Dissociation of (C 2 H 4 ) n •+ in the zeolite to give H + C 4 H 7 + could lead to ethyl radical in ZSM5 by H addition to ethylene; alternatively, ethyl radical may be produced directly by dissociation to give C 2 H 5 • + C 2 H 3 + .…”

Section: Discussionmentioning

confidence: 99%

Hydrogen Atom Addition to Hydrocarbon Guests in Radiolyzed Zeolites

et al. 1999

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The formation of H adducts during radiolysis of zeolites containing olefinic and aromatic hydrocarbon guests was demonstrated to occur by H atom transfer from the zeolite to the adsorbed molecules. The H adducts and other paramagnetic radiolysis products (radical cations and H-loss radicals) were detected by EPR spectroscopy. The mechanism of H adduct formation was confirmed by, inter alia, H/D isotopic labeling and comparison of results in HZSM5 and H−Mordenite to results in their Na+-exchanged counterparts. The effects of charge transfer among radiolysis products and zeolite−adsorbate interactions on the relative yields of trapped species is discussed. It is proposed that molecules smaller that a critical size adsorb inhomogeneously in ZSM5, forming aggregates in which ion−molecule reactions occur. Interpretation of the experimental results was aided by quantum chemical calculations of the molecular properties of the intermediates and their reaction energetics. This included evaluation of electron-transfer exothermicities, activation energies for H addition, and the relative acidities of the radical cations.

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Section: Discussionmentioning

confidence: 99%

Hydrogen Atom Addition to Hydrocarbon Guests in Radiolyzed Zeolites

et al. 1999

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“…Details can be found in previous publications. [15][16][17] III. RESULTS Figure 1 shows a typical mass spectrum of h 6 /d 6 -acetone obtained by temporally overlap the pumping beam of 390 nm and the probing beam of 780 nm.…”

Section: Experimental Methodsmentioning

confidence: 99%

Ultrafast dissociation dynamics of acetone: A revisit to the S1 state and 3s Rydberg state

Zhong

Poth

Castleman

1999

The Journal of Chemical Physics

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Because of the dispute in the literature over the dissociation rate and energy partitioning of the acetone molecule upon photoexcitation to the S 1 state (*←n) and 3s Rydberg state (3s←n), we have remeasured the lifetime of acetone ͑also d 6 -acetone͒ on the S 1 and 3s surfaces by a femtosecond time-resolved multiphoton ionization technique, coupled with a reflectron time-of-flight mass spectrometer. The measured dissociation rate of acetone on the S 1 surface is prompt, and the acetyl radical is long lived. The lifetime of acetone on the 3s surface is measured to be 3.2Ϯ0.4 ps ͑6.0Ϯ0.5 ps for d 6 -acetone͒. The dissociation rate of acetyl is approximately 1.7 ps ͑2.5 ps for d 3 -acetyl͒ from the curve fitting. This agrees well with the Rice-Ramsperger-Kassel-Marcus theory predicted lifetime of 1.0 ps ͑1.9 ps for d 3 -acetyl͒ when the internal excitation energy of the acetyl radical is treated by a statistical-adiabatic-impulsive model.

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“…[17][18][19][20] Briefly, a molecular beam comprised of monomers of HCl, DCl, HBr, and DBr seeded in argon was produced by mixing 300 Torr of DCl and HBr ͑Matheson gas͒ in argon. The gas mixture was then expanded through a pulsed nozzle ͑150 m diameter͒ with a total backing pressure of about 700 Torr.…”

Section: Methodsmentioning

confidence: 99%

“…The neutral species were then ionized with the femtosecond laser beam using a pump-probe scheme. 20,21 The laser system consists of a mode-locked Ti: sapphire oscillator pumped by a 10 W argon ion laser which generates an 82 MHz pulse train. The pulses are amplified by a regenerative Ti: sapphire amplifier pumped by the second harmonic of a 10 Hz Nd:YAG laser.…”

Section: Methodsmentioning

confidence: 99%

Dynamics of the E state of HBr and DBr: Evidence for the role of tunneling

Hurley

Zhong

Castleman

2000

The Journal of Chemical Physics

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Extensive ab initio study of the valence and low-lying Rydberg states of BBr including spin-orbit coupling A unified model of the dynamics and spectroscopy of the g 3 Σ 0 − and E 1 Σ + states of hydrogen chloride J. Chem. Phys. 108, 984 (1998); 10.1063/1.475461 Time and frequency resolved spectra of high molecular Rydberg states by dynamical computationsThe dynamics of the interaction of the Rydberg E( 1 ⌺ ϩ ) state and the valence state V( 1 ⌺ ϩ ) of HBr and DBr were investigated using a reflectron time-of-flight mass spectrometer coupled with a femtosecond laser system. Interrogation of the state formed by the avoided crossing of the Rydberg and valence states revealed dynamic behavior that was different for the two isotopes. Pump-probe experiments on HBr showed no change in the lifetime over the range of pump wavelengths of 256.7-254.7 nm. However, the lifetime of DBr decreased as the pump wavelength was tuned bluer. Tunneling is involved in the evolution of the population in photoexcited Rydberg state to the ion-pair state.

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Intracluster Polymerization Reactions of Alkene Cluster Ions

Cited by 25 publications

References 53 publications

Hydrogen Atom Addition to Hydrocarbon Guests in Radiolyzed Zeolites

Hydrogen Atom Addition to Hydrocarbon Guests in Radiolyzed Zeolites

Ultrafast dissociation dynamics of acetone: A revisit to the S1 state and 3s Rydberg state

Dynamics of the E state of HBr and DBr: Evidence for the role of tunneling

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