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U.S. Department of Energy
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Reactions of small molecular systems

Technical Report ·
OSTI ID:5555957

In this report, we present the C{sub 2}H{sub 2} + hv(193.3 nm) {yields} H + C{sub 2}H translational energy distribution. A C{sub 2}H bending progression dominates the distribution. The Rydberg time of flight (TOF) method offers high resolution (10's of cm{sup {minus}1}), which may ultimately be needed to establish D{sub 0} doubt. The method of detecting H atoms via 2-photon, 2-frequency excitation to a high-lying Rydberg state followed by efficient field ionization was used. Briefly an expansion of C{sub 2}H{sub 2} seeded in He is skimmed and crossed with the output from an ArF laser. H-atoms are excited by VUV radiation tuned to 121.6 nm (Lyman-{alpha}). This is generated by tripling the output of a 364.7 nm dye laser in Kr. Another laser beam, overlapping the 121.6 nm beam, transfers population from the 2{sup 2}P level to a high-lying Rydberg level. Such levels are metastable and remain excited or many 10's of {mu}s. These atoms travel to a detector 23.6 cm from the interaction region; since the atoms are neutral, they are not affected by space charge. As the atoms arrive at the detector, they are field-ionized and detected as ions. TOF spectra are recorded using a transient digitizer and a computer. 27 refs., 2 figs.

Research Organization:
University of Southern California, Los Angeles, CA (United States). Dept. of Chemistry
Sponsoring Organization:
DOE; USDOE, Washington, DC (United States)
DOE Contract Number:
FG03-85ER13363
OSTI ID:
5555957
Report Number(s):
DOE/ER/13363-T2; ON: DE91014519
Country of Publication:
United States
Language:
English