In:
The Journal of Chemical Physics, AIP Publishing, Vol. 117, No. 3 ( 2002-07-15), p. 1040-1046
Abstract:
The excitation spectra of the D̃ 1Πu, Ẽ 1A, and F̃ 1Σu+ states of C2H2 in the 135.3–130.8 nm range are measured under jet-cooled conditions by detecting fluorescence emitted from C2H(Ã 2Π) or C2H(B̃ 2A′) photofragments. In the photofragment emission yield spectra, the origin bands of the D̃–X̃ and F̃–X̃ transitions are observed with Lorentzian profiles with bandwidth (Γ) of 58.9(4) and 66.7(2) cm−1, respectively. By identifying the bending progressions of the Ẽ–X̃ transition appearing with narrower Lorentzian profiles with, Γ∼40 cm−1, the band previously considered to be the origin band of the Ẽ–X̃ transition is assigned to the transition to the second overtone (v3=3) level in the near-cis bending (ν3) mode. The transitions to the C–H stretch excited levels in the D̃ and F̃ states are observed using the infrared-VUV double resonance excitation scheme. The D̃ 311, D̃ 111 311, F̃ 311, and F̃ 111 311 bands are identified at 74 334(3), 74 121(5), 74 522(3), and 74 388(3) cm−1, respectively, with much broader bandwidth (Γ & gt;100 cm−1) than the D̃–X̃ and F̃–X̃ origin bands, indicating that the dissociation is accelerated significantly in both of the D̃ and F̃ states when the antisymmetric C–H stretch (ν3) mode in the D̃ and F̃ states is excited.
Type of Medium:
Online Resource
ISSN:
0021-9606
,
1089-7690
Language:
English
Publisher:
AIP Publishing
Publication Date:
2002
detail.hit.zdb_id:
3113-6
detail.hit.zdb_id:
1473050-9
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