Pulsed laser photodissociation of chromium hexacarbonyl at 308 nm: simultaneous monitoring of optical and acoustic emissions

✍ Scribed by Nai-Ho Cheung; Edward S. Yeung

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 581 KB
• Volume: 189
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(92)85117-s

✦ Synopsis

A novel, yet simple, acoustic technique wa applied to measure the molar number of fragments formed in the XeCl laser-induced gas-phase photodissociation of Cr(CO),.

The bluish-green Cr emission was also monitored and correlated with the acoustic signal. At 0. I6 Torr of hexacarbonyl and for fluences below z 25 mJ/cm', the optical signal varied as the cube of the laser fluence, in agreement with the model that highly excited Cr atoms were produced by three-photon processes. The acoustic signal y (mV) varied with fluence F (ml/cm') as y= 1.77F+ 0.1 SF*, consistent with the model that most fragments were formed via two sequential single-photon processes. Both optical and acoustic signals showed onset of saturation at = 25 mJ/cm2, suggesting that single-photon photolysis was the primary Cr(C0)6 depletion process. Quite expectedly, with a constant fluence of = 20 mJ/cm' and varying hexacarbonyl pressure, the optical and acoustic signals were linearly correlated.