In:
The Journal of Chemical Physics, AIP Publishing, Vol. 94, No. 12 ( 1991-06-15), p. 7832-7841
Abstract:
The multiphoton dissociation processes of acetylene via a two-photon resonant predissociative state, v=0 of 1Σ+g, have been studied by three techniques: time-resolved photofragment excitation spectroscopy (TRPFES), laser-induced fluorescence (LIF) of the C2 fragments, and dispersed emission. We found that the major dissociation products are H atoms, H2 molecules, and C2 molecules in the X 1Σ+g, a 3Πu and A 1Πu states; among the latter, C2 X 1Σ+g molecules are formed by a sequential bond–rupture mechanism whereas some C2 in a 3Πu is formed by a concerted two-bond fission process. Other, minor dissociation channels due to three-photon processes, such as C2(d 3Πg)+2H(2S(1)/(2)), C2(d 3Πg)+H2(X 1Σ+g), C2(C 1Πg)+H2(X), C2(e 3Πg)+H2(X), and C2(D 1Σ+u)+H2(X), were also detected. In the 2+1 concerted dissociation yielding C2(C 1Πg)+H2(X), a long-lived intermediate C2H2, likely a cis isomer or other conformer in which the hydrogen atoms are relatively close to each other, was revealed by TRPFES; its zero-pressure lifetime was estimated to be (8±1) μs. A long-lived intermediate C2H was also found in the 2+1 sequential dissociation by TRPFES.
Type of Medium:
Online Resource
ISSN:
0021-9606
,
1089-7690
Language:
English
Publisher:
AIP Publishing
Publication Date:
1991
detail.hit.zdb_id:
3113-6
detail.hit.zdb_id:
1473050-9
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