Direct measurement of the Rayleigh scattering cross section in various gases

✍ Scribed by Maarten Sneep; Wim Ubachs

• Book ID: 104027898
• Publisher: Elsevier Science
• Year: 2005
• Tongue: English
• Weight: 820 KB
• Volume: 92
• Category: Article
• ISSN: 0022-4073
• DOI: 10.1016/j.jqsrt.2004.07.025

✦ Synopsis

Using the laser-based technique of cavity ring-down spectroscopy extinction measurements have been performed in various gases straightforwardly resulting in cross sections for Rayleigh scattering. For Ar and N

2

measurements are performed in the range 470–490nm, while for CO

2

cross sections are determined in the wider range 470–570nm. In addition to these gases also for N

2

O, CH

4

, CO, and SF

6

the scattering cross section is determined at 532nm, a wavelength of importance for lidar applications and combustion laser diagnostics. In O

2

the cross section at 532nm is found to depend on pressure due to collision-induced light absorption. The obtained cross sections validate the cross sections for Rayleigh scattering as derived from refractive indices and depolarization ratios through Rayleigh's theory at the few %-level, although somewhat larger discrepancies are found for CO, N

2

O and CH

4

.