PMID- 19204957
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20090624
LR  - 20090310
IS  - 1439-7641 (Electronic)
IS  - 1439-4235 (Linking)
VI  - 10
IP  - 4
DP  - 2009 Mar 9
TI  - Probing the ignored elimination channel of Br2 in the 248 nm photodissociation of 
      1,1-dibromoethylene by cavity ring-down absorption spectroscopy.
PG  - 672-9
LID - 10.1002/cphc.200800665 [doi]
AB  - In the photodissociation of 1,1-C(2)H(2)Br(2) at 248 nm, the Br(2) elimination 
      channel is probed by using cavity ring-down absorption spectroscopy (CRDS). In 
      terms of spectral simulation, the vibrational population ratio of Br(2)(v = 
      1)/Br(2)(v = 0) is found to be 0.55+/-0.05, which indicates that the Br(2) 
      fragment is vibrationally hot. The rotational population is thermally 
      equilibrated with a Boltzmann temperature of 349+/-38 K. According to ab initio 
      potential energy calculations, the obtained fragments are anticipated to result 
      primarily from photodissociation of the ground electronic state that undergoes 1) 
      H migration followed by three-center elimination, and 2) isomerization forming 
      either trans- or cis-1,2-C(2)H(2)Br(2) from which Br(2) is eliminated. RRKM 
      calculations predict that the Br(2) dissociation rates through the ground singlet 
      state prevail over those through the triplet state. Measurements of temperature 
      and Ar pressure dependence are examined to support the proposed pathway via 
      internal conversion. The quantum yield for the Br(2) elimination reaction is 
      determined to be 0.07+/-0.04. This result is smaller than that obtained in 
      1,2-C(2)H(2)Br(2), probably because the dissociation rates are slowed in the 
      isomerization stage.
FAU - Lee, Ping-Chen
AU  - Lee PC
AD  - Department of Chemistry, National Taiwan University, Taipei and Institute of 
      Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan.
FAU - Tsai, Po-Yu
AU  - Tsai PY
FAU - Hsiao, Ming-Kai
AU  - Hsiao MK
FAU - Lin, King-Chuen
AU  - Lin KC
FAU - Huang, C H
AU  - Huang CH
FAU - Chang, A H H
AU  - Chang AH
LA  - eng
PT  - Journal Article
PL  - Germany
TA  - Chemphyschem
JT  - Chemphyschem : a European journal of chemical physics and physical chemistry
JID - 100954211
EDAT- 2009/02/11 09:00
MHDA- 2009/02/11 09:01
CRDT- 2009/02/11 09:00
PHST- 2009/02/11 09:00 [entrez]
PHST- 2009/02/11 09:00 [pubmed]
PHST- 2009/02/11 09:01 [medline]
AID - 10.1002/cphc.200800665 [doi]
PST - ppublish
SO  - Chemphyschem. 2009 Mar 9;10(4):672-9. doi: 10.1002/cphc.200800665.