Absolute primary H atom quantum yield measurements in the 193.3 and 121.6 nm photodissociation of acetylene

Läuter, Almuth; Lee, K.S.; Jung, Kyung‐Hoon; Vatsa, R.K.; Mittal, Jai P.; Volpp, Hans-Robert

doi:10.1016/s0009-2614(02)00625-5

Cited by 58 publications

(40 citation statements)

References 33 publications

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“…It is important to stress that the benzene molecule (C 6 H 6 ) [44][45][46] is present in the atmosphere of Titan along with highly reactive ethynyl radicals (C 2 H); the latter are predominantly formed from the solar ultraviolet photolysis of acetylene at wavelengths below 200 nm. [47][48][49][50][51] Therefore, the present crossed beam study of the perdeutero variant of the ethynyl radical with benzene is aimed to extract the underlying chemical dynamics together with potential reaction intermediates and the final reaction product under single collision conditions to shed light if the phenylacetylene molecule can be formed via a barrierless reaction of benzene with the ethynyl radical.…”

Section: Introductionmentioning

confidence: 99%

Crossed Molecular Beam Study on the Formation of Phenylacetylene and Its Relevance to Titan’s Atmosphere

et al. 2010

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The crossed molecular beam experiment of the deuterated ethynyl radical (C 2 D; X 2 Σ + ) with benzene [C 6 H 6 (X 1 A 1g )] and its fully deuterated analog [C 6 D 6 (X 1 A 1g )] was conducted at a collision energy of 58.1 kJ mol -1 . Our experimental data suggest the formation of the phenylacetylene-d 6 via indirect reactive scattering dynamics through a long-lived reaction intermediate; the reaction is initiated by a barrierless addition of the ethynyl-d 1 radical to benzene-d 6 . This initial collision complex was found to decompose via a tight exit transition state located about 42 kJ mol -1 above the separated products; here, the deuterium atom is ejected almost perpendicularly to the rotational plane of the decomposing intermediate and almost parallel to the total angular momentum vector. The overall experimental exoergicity of the reaction is shown to be 121 ( 10 kJ mol -1 ; this compares nicely with the computed reaction energy of -111 kJ mol -1 . Even though the experiment was conducted at a collisional energy higher than equivalent temperatures typically found in the atmosphere of Titan (94 K and higher), the reaction may proceed in Titan's atmosphere as it involves no entrance barrier, all transition states involved are below the energy of the separated reactants, and the reaction is exoergic. Further, the phenylacetylene was found to be the sole reaction product.

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Section: Introductionmentioning

confidence: 99%

Crossed Molecular Beam Study on the Formation of Phenylacetylene and Its Relevance to Titan’s Atmosphere

et al. 2010

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“…Electronic mail: val@irsamc.ups-tlse.fr CHϩCH and C 2 ϩH 2 channels are not open at 9.4 eV because the dissociation threshold is at a higher energy for the latter channel, while the former channel is accompanied by a high energy barrier. 12,13 The density of states is generally high in molecules where close-lying electronic states have overlapping vibrational progressions. Complete selectivity in the excitation of a vibrational sublevel requires narrow bandwidth pulses.…”

Section: Introductionmentioning

confidence: 99%

The predissociation of highly excited states in acetylene by time-resolved photoelectron spectroscopy

Zamith

Blanchet

Girard

et al. 2003

The Journal of Chemical Physics

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We study the dynamics of highly excited states in acetylene initiated by an ultrashort vacuum ultraviolet laser pulse. Electronic states lying in the 4s-3d Rydberg region are excited with one femtosecond pulse, and the dynamic development of the states is monitored by a second short pulse which ionizes the system. We show that even for femtosecond pulses where the bandwidth of the exciting pulse covers several electronic states, it is possible to extract short decay lifetimes through time-resolved photoelectron spectroscopy by using a frequency-modulated ͑chirped͒ excitation pulse. We report decay lifetimes for the F 4 0 2 and E 4-5 0 2 states in acetylene, and for the E 4 0 2 and E 5 0 2 states in d-acetylene. The time evolution measured in the electron spectra is compared to decay spectra measured using ion yield and the differences in these results are discussed.

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“…2, 8 Several experimental and theoretical investigations have been carried out to study the C 2 H radical reactivity, [9][10][11] its absorption spectroscopy, [12][13][14][15][16][17] and its production from acetylene photolysis. [18][19][20][21] Although a few theoretical works have been performed on the C 2 H + cation, [22][23][24][25] the experimental studies of this cation are scarcer. 12,26,27 Finally only three studies have measured indirectly the ionization energy (IE) of this important radical [28][29][30] and no experimental works have been published about its photoionizing transitions to our knowledge.…”

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confidence: 99%

Communication: On the first ionization threshold of the C2H radical

Gans

Garcia

Holzmeier

et al. 2017

The Journal of Chemical Physics

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The slow photoelectron spectrum of the ethynyl radical has been recorded for the first time by using the DESIRS beamline of the SOLEIL synchrotron facility. Ethynyl was generated using a microwave discharge flow tube. The observation of the X+Π3←XΣ+2 transition allowed the first direct measurement of the adiabatic ionization threshold of this radical (EI = 11.641(5) eV). The experimental results are supported by ab initio calculations. Our preliminary investigation of the cationic ground state potential energy surfaces predicts a non-negligible Renner-Teller effect which has not been discussed previously.

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Absolute primary H atom quantum yield measurements in the 193.3 and 121.6 nm photodissociation of acetylene

Cited by 58 publications

References 33 publications

Crossed Molecular Beam Study on the Formation of Phenylacetylene and Its Relevance to Titan’s Atmosphere

Crossed Molecular Beam Study on the Formation of Phenylacetylene and Its Relevance to Titan’s Atmosphere

The predissociation of highly excited states in acetylene by time-resolved photoelectron spectroscopy

Communication: On the first ionization threshold of the C2H radical

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