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Photodissociation processes in molecular beams

Technical Report ·
DOI:https://doi.org/10.2172/6027267· OSTI ID:6027267
A description is presented of a study of the photodissociation dynamics of molecules in a molecular beam. Photo-fragmentation translational spectroscopy has been utilized to observe the photodissociation dynamics of ozone. Using a supersonic molecular beam and a 10 nanosecond pulsed laser at lambda = 266 nm, the velocities of the fragment products are measured by the method of time of flight. The resolution of the time of flight spectrum of ozone is sufficiently high that the electronic and vibrational states are clearly resolved and identified. Above the threshold (lambda < 310 nm), the quantum yield for the production of O(/sup 1/D) has been estimated in the past to be unity for the process O/sub 3/ (/sup 1/A/sub 1/) + h..nu..)lambda < 300 nm) ..-->.. O/sub 3/(/sup 1/B/sub 2/) ..-->.. O/sub 2/(/sup 1/..delta../sub g/) + O(/sup 1/D). However a small production of O/sub 2/ (/sup 3/..sigma../sub g//sup -/) + O(/sup 3/P) has been observed in this study. The O/sub 2/(/sup 1/..delta../sub g/) product yields four vibrational states (v = 0, 1, 2, 3) which yields a vibrational temperature of 2700/sup 0/K along with narrow energy distributions of rotational levels. These energy distributions are compared with photodissociation models along with the polarization dependence of the dissociative process which was also measured. 143 references.
Research Organization:
California Univ., Berkeley (USA). Lawrence Berkeley Lab.; California Univ., Berkeley (USA). Dept. of Chemistry
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
6027267
Report Number(s):
LBL-9219
Country of Publication:
United States
Language:
English