Isotope effects in the dissociation of the B-tilde{sup 1}A{sub 1} state of SiH{sub 2}, SiHD, and SiD{sub 2} using three-dimensional wave packet propagation

Journal Article · Tue Mar 21 04:00:00 EST 2006 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.2183301· OSTI ID:20783245

Tokue, Ikuo; Yamasaki, Katsuyoshi; Nanbu, Shinkoh ^[1]

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1. Department of Chemistry, Faculty of Science, Niigata University, Ikarashi, Niigata 950-2181 (Japan)

Dissociations after the A-tilde{sup 1}B{sub 1}{yields}B-tilde{sup 1}A{sub 1} photoexcitation of SiH{sub 2}, SiHD, and SiD{sub 2} were studied to investigate excited-state dynamics and effects of the initial vibrational state. The cross section ({sigma}) for the photodissociation relative to SiH{sub 2}(B-tilde){yields}Si({sup 1}D)+H{sub 2} and the rovibrational population of the H{sub 2} fragment were computed using the wave packet propagation technique based on the three-dimensional potential energy surfaces (PESs) of the A-tilde and B-tilde electronic states and the transition dipole surfaces, which were reported in our previous paper [J. Chem. Phys. 122, 144307 (2005)]. The photodissociation spectrum consists of a broadband and a number of sharp peaks. For SiH{sub 2} and SiD{sub 2}, the sharp peaks correspond to the resonance structure of the vibrational levels of the B-tilde state and the broadbands are nearly independent of the photon energy. The broadband for SiHD increases steeply with the photon energy above 30,000 cm{sup -1}. The flux leaving the computational grid for SiH{sub 2} and SiD{sub 2} consists of at least two components, whereas that for SiHD consists of only a faster component. These large isotope effects were discussed based on the valley to the dissociation channel on PES and the difference in the position of the initial wave packet for three isotopomers.

• OSTI ID: 20783245
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 11 Vol. 124; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CROSS SECTIONS
DEUTERIDES
DISSOCIATION
HYDRIDES
HYDROGEN
ISOTOPE EFFECTS
PHOTOLYSIS
PHOTON-MOLECULE COLLISIONS
REACTION KINETICS
SILICON COMPOUNDS
THREE-DIMENSIONAL CALCULATIONS
VIBRATIONAL STATES
WAVE PACKETS