Photoacoustic overtone spectroscopy of liquids with continuous wave laser excitation

✍ Scribed by Carlos Manzares I

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 700 KB
• Volume: 181
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(91)90220-4

✦ Synopsis

To study overtone absorptions in condensed phases, a technique is presented which uses a piezoelectric detector, lock-in ampliticatlon and a cw dye laser modulated at frequencies from 10 to 120 kHz with an acousto-optic modulator. Acoustic resonance frequencies calculated for a cylindrical cell are observed experimentally using liquid Si (CH,), as the sample. The acoustic signal is found to be proportional to the laser power. The fifth overtone of the C-H stretching mode ofSi( CH3)., has been recorded pure and in solutions with Ccl,. With a 1% solution of Si(CH3)4 in Ccl,, an absorbance ofapproximately I x 10e5 cm-' is detected with a dye laser power of 55 mW