Photolysis atomic resonance line

Fig. 3. Transient profile of O ( Pj) density obtained by monitoring the vacuum ultraviolet atomic resonance fluorescence signal following laser photodissociation of O3. (a) Photolysis at 308 nm, Pqs = 1 mTorr, Pjjg = 5.7 Tort, 40288 averaged, (b) Photolysis at 248 nm, Pon = f mTorr, Pjj = 9.7 Torr, 8192 shots averaged. The solid lines through the points representing non-linear least squares fit to the data. [Source Greenblatt and Wiesenfeld, 1983].

The possibility of mercury-photosensitized reactions was first predicted in 1922 by Franck (45) and experimentally verified in the sensitized decomposition of H2 by Cario and Franck (46). They found that free H atoms were produced when a mixture of Hg vapor and H2 was irradiated with the 254 nm Hg resonance line at room temperature. Bates and Taylor (23) studied the Hg-sensitized decomposition of methanol, ethanol, and ethylamine, and showed that with these compounds the rate of the sensitized reaction was faster than the direct photolysis by about two orders of magnitude. Again hydrogen was the major product. Aldehydes were formed from the alcohols. 

For excitation in the vacuum-u.v. region, several atomic resonance lamps have been employed. Hg, Zn, and Cd emission lines were used in the photolysis of gaseous tetramethylethylene over the excitation range 185—230 nm. The photolysis of methylsilane (at 147 and pent-l-ene (at 123.7was... 

---