On the ultraviolet photodissociation of H{sub 2}Te
- Fachbereich C-Theoretische Chemie, Bergische Universitaet Wuppertal, Gaussstrasse 20, D-42097 Wuppertal (Germany)
The photodissociation of H{sub 2}Te through excitation in the first absorption band is investigated by means of multireference spin-orbit configuration interaction (CI) calculations. Bending potentials for low-lying electronic states of H{sub 2}Te are obtained in C{sub 2v} symmetry for Te-H distances fixed at the ground state equilibrium value of 3.14a{sub 0}, as well as for the minimum energy path constrained to R{sub 1}=R{sub 2}. Asymmetric cuts of potential energy surfaces for excited states (at R{sub 1}=3.14a{sub 0} and {theta}=90.3 deg.) are obtained for the first time. It is shown that vibrational structure in the 380-400 nm region of the long wavelength absorption tail is due to transitions to 3A{sup '}, which has a shallow minimum at large HTe-H separations. Transitions to this state are polarized in the molecular plane, and this state converges to the excited TeH({sup 2}{pi}{sub 1/2})+H({sup 2}S) limit. These theoretical data are in accord with the selectivity toward TeH({sup 2}{pi}{sub 1/2}) relative to TeH({sup 2}{pi}{sub 3/2}) that has been found experimentally for 355 nm H{sub 2}Te photodissociation. The calculated 3A{sup <}-X-tildeA{sup '} transition dipole moment increases rapidly with HTe-H distance; this explains the observation of 3A{sup '} vibrational structure for low vibrational levels, despite unfavorable Franck-Condon factors. According to the calculated vertical energies and transition moment data, the maximum in the first absorption band at {approx_equal}245 nm is caused by excitation to 4A{sup ''}, which has predominantly 2{sup 1}A{sup ''} ({sup 1}B{sub 1} in C{sub 2v} symmetry) character.
- OSTI ID:
- 20658054
- Journal Information:
- Journal of Chemical Physics, Vol. 121, Issue 19; Other Information: DOI: 10.1063/1.1799572; (c) 2004 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
Similar Records
248 nm photolysis of CH{sub 2}Br{sub 2} by using cavity ring-down absorption spectroscopy: Br{sub 2} molecular elimination at room temperature
Br{sub 2} elimination in 248-nm photolysis of CF{sub 2}Br{sub 2} probed by using cavity ring-down absorption spectroscopy
Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION
BOND LENGTHS
CONFIGURATION INTERACTION
DIPOLE MOMENTS
DISSOCIATION
EXCITATION
GROUND STATES
L-S COUPLING
MOLECULAR STRUCTURE
PHOTOLYSIS
PHOTON-MOLECULE COLLISIONS
TELLURIUM HYDRIDES
THEORETICAL DATA
ULTRAVIOLET RADIATION
ULTRAVIOLET SPECTRA
VIBRATIONAL STATES