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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
2004-7-22
pubmed:abstractText
The excited state hydrogen atom transfer reaction (ESHT) has been studied in pyrrole-ammonia clusters [PyH-(NH(3))(n)+hnu-->Py.+.NH(4)(NH(3))(n-1)]. The reaction is clearly evidenced through two-color R2P1 experiments using delayed ionization and presents a threshold around 235 nm (5.3 eV). The cluster dynamics has also been explored by picosecond time scale experiments. The clusters decay in the 10-30 ps range with lifetimes increasing with the cluster size. The appearance times for the reaction products are similar to the decay times of the parent clusters. Evaporation processes are also observed in competition with the reaction, and the cluster lifetime after evaporation is estimated to be around 10 ns. The kinetic energy of the reaction products is fairly large and the energy distribution seems quasi mono kinetic. These experimental results rule out the hypothesis that the reaction proceeds through a direct N-H bond rupture but rather imply the existence of a fairly long-lived intermediate state. Calculations performed at the CASSCF/CASMP2 level confirm the experimental observations, and provide some hints regarding the reaction mechanism.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9606
pubmed:author
pubmed:copyrightInfo
(c) 2004 American Institute of Physics.
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
120
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10101-10
pubmed:year
2004
pubmed:articleTitle
Hydrogen transfer in excited pyrrole-ammonia clusters.
pubmed:affiliation
Laboratoire de Photophysique Moléculaire du CNRS, Bât. 210 Université Paris-Sud, 91405 Orsay, France.
pubmed:publicationType
Journal Article