Aufsatz
Femtosecond real-time probing of reactions. 12. Vectorial dynamics of transition states
Zusammenfassung
Femtosecond time-resolved techniques with KETOF (kinetic energy time-of-flight) detection in a molecular beam are developed for studies of the vectorial dynamics of transition states. Application to the dissociation reaction of IHgI is presented. For this system, the complex [I---Hg---I](++)* is unstable and, through the symmetric and asymmetric stretch motions, yields different product fragments: [I---Hg---I](++)* -> HgI(X^2/sigma^+) + I(^2P_3/2) [or I*(^2P_l/2)] (1a); [I---Hg---I](++)* -> Hg(^1S_0) + I(^2P_3/2) + I(^2P_3/2) [or I* (^2P_1/2)] (1 b). These two channels, (1a) and (1b), lead to different kinetic energy distributions in the products. It is shown that the motion of the wave packet in the transition-state region can be observed by MPI mass detection; the transient time ranges from 120 to 300 fs depending on the available energy. With polarized pulses, the vectorial properties (transition moments alignment relative to recoil direction) are studied for fragment separations on the femtosecond time scale. The results indicate the nature of the structure (symmetry properties) and the correlation to final products. For 311-nm excitation, no evidence of crossing between the I and I* potentials is found at the internuclear separations studied. (Results for 287-nm excitation are also presented.) Molecular dynamics simulations and studies by laser-induced fluorescence support these findings.
Zitierform
In: Journal of physical chemistry. Washington, DC : American Chemical Society. 97 (1993), S. 12447-12459Sammlung(en)
Publikationen (Experimentalphysik III - Femtosekundenspektroskopie und ultraschnelle Laserkontrolle)Zitieren
@article{urn:nbn:de:hebis:34-2008102724809,
author={Baumert, Thomas and Pedersen, S. and Zewail, Ahmed Hassan},
title={Femtosecond real-time probing of reactions. 12. Vectorial dynamics of transition states},
year={1993}
}
0500 Oax 0501 Text $btxt$2rdacontent 0502 Computermedien $bc$2rdacarrier 1100 1993$n1993 1500 1/eng 2050 ##0##urn:nbn:de:hebis:34-2008102724809 3000 Baumert, Thomas 3010 Pedersen, S. 3010 Zewail, Ahmed Hassan 4000 Femtosecond real-time probing of reactions. 12. Vectorial dynamics of transition states / Baumert, Thomas 4030 4060 Online-Ressource 4085 ##0##=u http://nbn-resolving.de/urn:nbn:de:hebis:34-2008102724809=x R 4204 \$dAufsatz 4170 7136 ##0##urn:nbn:de:hebis:34-2008102724809
2008-10-27T08:47:22Z 2008-10-27T08:47:22Z 1993 0022-3654 0092-7325 urn:nbn:de:hebis:34-2008102724809 http://hdl.handle.net/123456789/2008102724809 1536505 bytes application/pdf eng Urheberrechtlich geschützt https://rightsstatements.org/page/InC/1.0/ 530 Femtosecond real-time probing of reactions. 12. Vectorial dynamics of transition states Aufsatz Femtosecond time-resolved techniques with KETOF (kinetic energy time-of-flight) detection in a molecular beam are developed for studies of the vectorial dynamics of transition states. Application to the dissociation reaction of IHgI is presented. For this system, the complex [I---Hg---I](++)* is unstable and, through the symmetric and asymmetric stretch motions, yields different product fragments: [I---Hg---I](++)* -> HgI(X^2/sigma^+) + I(^2P_3/2) [or I*(^2P_l/2)] (1a); [I---Hg---I](++)* -> Hg(^1S_0) + I(^2P_3/2) + I(^2P_3/2) [or I* (^2P_1/2)] (1 b). These two channels, (1a) and (1b), lead to different kinetic energy distributions in the products. It is shown that the motion of the wave packet in the transition-state region can be observed by MPI mass detection; the transient time ranges from 120 to 300 fs depending on the available energy. With polarized pulses, the vectorial properties (transition moments alignment relative to recoil direction) are studied for fragment separations on the femtosecond time scale. The results indicate the nature of the structure (symmetry properties) and the correlation to final products. For 311-nm excitation, no evidence of crossing between the I and I* potentials is found at the internuclear separations studied. (Results for 287-nm excitation are also presented.) Molecular dynamics simulations and studies by laser-induced fluorescence support these findings. open access In: Journal of physical chemistry. Washington, DC : American Chemical Society. 97 (1993), S. 12447-12459 Baumert, Thomas Pedersen, S. Zewail, Ahmed Hassan Extern
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