TY - JOUR
T1 - Neutral excited radicals formed by ethylene photodissociation in the 8-24eV region
AU - O'Reilly, John
AU - Alnama, Koutayba
AU - Boyé, Séverine
AU - Douin, Stéphane
AU - Innocenti, Fabrizio
AU - Roche, Anne Lise
AU - Shafizadeh, Niloufar
AU - Zuin, Lucia
AU - Gauyacq, Dolores
PY - 2004/5/7
Y1 - 2004/5/7
N2 - Dissociation pathways following photolysis of ethylene C2H 4 in the 6.2-24.8 eV energy range, and leading to excited fragment production are investigated. The dispersed visible fluorescence of the products has been recorded for a large range of excitation energies, allowing for the determination of experimental energy thresholds for the different pathways. It is found that the C2H (Ã) radical is the dominant fragment, emitting in the visible range. It is formed with a considerable amount of vibrational excitation energy, as was previously reported in the photodissociation study of acetylene C2H2. From the dissociation threshold measurements, several barrierless processes are evidenced. In particular, the excited CH* (A or B) radical is formed via an intermediate isomer, ethylidene, with no excess energy. More surprisingly, all channels involving one H2 molecular elimination are observed without any barrier, unlike the dissociation processes occurring on the ground state potential energy surface (PES) of C2H4. Most probably, this observation originates from an easier relaxation of the excited state into pyramidalised states.
AB - Dissociation pathways following photolysis of ethylene C2H 4 in the 6.2-24.8 eV energy range, and leading to excited fragment production are investigated. The dispersed visible fluorescence of the products has been recorded for a large range of excitation energies, allowing for the determination of experimental energy thresholds for the different pathways. It is found that the C2H (Ã) radical is the dominant fragment, emitting in the visible range. It is formed with a considerable amount of vibrational excitation energy, as was previously reported in the photodissociation study of acetylene C2H2. From the dissociation threshold measurements, several barrierless processes are evidenced. In particular, the excited CH* (A or B) radical is formed via an intermediate isomer, ethylidene, with no excess energy. More surprisingly, all channels involving one H2 molecular elimination are observed without any barrier, unlike the dissociation processes occurring on the ground state potential energy surface (PES) of C2H4. Most probably, this observation originates from an easier relaxation of the excited state into pyramidalised states.
UR - http://www.scopus.com/inward/record.url?scp=2942562615&partnerID=8YFLogxK
U2 - 10.1039/b316056d
DO - 10.1039/b316056d
M3 - Article
AN - SCOPUS:2942562615
SN - 1463-9076
VL - 6
SP - 2093
EP - 2100
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 9
ER -