TY - JOUR
T1 - Overtone-induced chemistry of trifluoroacetic acid
T2 - An experimental and theoretical study
AU - Reynard, Linda M.
AU - Donaldson, D. J.
PY - 2002/9/19
Y1 - 2002/9/19
N2 - The effect of overtone-induced chemistry on the atmospheric fate of trifluoroacetic acid has been investigated. We report the absolute absorption intensities for the vOH = 3, 4, and 5 overtone transitions as well as an ab initio calculation of the energetics of the dissociation pathways. Calculations at the MP2 level give the lowest dissociation barrier as 50.3 kcal mol-1 for the elimination of HF. Integrated cross sections for vOH = 3, 4, and 5 are 2.70 × 10-20, 1.68 × 10-21, and 1.5 × 10-22 cm2 molecule-1 cm-1, respectively. Dissociation may proceed after absorption into v = 5 or 6, giving an upper limit to the photodissociation rate constants of 3.7 × 10-9 s-1 or 2.5 × 10-10 s-1, respectively. These correspond to a tropospheric lifetime of between 8 and 127 years. The overtone-driven photodissociation is more important than the ultraviolet photodissociation in the troposphere but is insignificant in comparison to wet deposition and the reaction with OH radicais.
AB - The effect of overtone-induced chemistry on the atmospheric fate of trifluoroacetic acid has been investigated. We report the absolute absorption intensities for the vOH = 3, 4, and 5 overtone transitions as well as an ab initio calculation of the energetics of the dissociation pathways. Calculations at the MP2 level give the lowest dissociation barrier as 50.3 kcal mol-1 for the elimination of HF. Integrated cross sections for vOH = 3, 4, and 5 are 2.70 × 10-20, 1.68 × 10-21, and 1.5 × 10-22 cm2 molecule-1 cm-1, respectively. Dissociation may proceed after absorption into v = 5 or 6, giving an upper limit to the photodissociation rate constants of 3.7 × 10-9 s-1 or 2.5 × 10-10 s-1, respectively. These correspond to a tropospheric lifetime of between 8 and 127 years. The overtone-driven photodissociation is more important than the ultraviolet photodissociation in the troposphere but is insignificant in comparison to wet deposition and the reaction with OH radicais.
UR - http://www.scopus.com/inward/record.url?scp=0037136626&partnerID=8YFLogxK
U2 - 10.1021/jp021084w
DO - 10.1021/jp021084w
M3 - Article
AN - SCOPUS:0037136626
SN - 1089-5639
VL - 106
SP - 8651
EP - 8657
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 37
ER -