Abstract
Absorptivity measurements for the 3.39 μm He-Ne laser line are reported for acetylene, ethylene, and propylene over the temperature ranges 1500 to 3000 K (acetylene), 1000 to 2000 K (ethylene), and 700 to 2300 K (propylene). In contrast to the behavior of other hydrocarbons, the absorptivities of acetylene and ethylene increase with increasing temperature. The conventional spectroscopic analysis of line positions based upon high-resolution infrared spectroscopy at room temperature and approximate line-broadening theory indicate that no absorption at all would be expected for acetylene or ethylene. The time-resolved absorption profiles and computer models of the chemical behavior expected for shock-heated test gas confirm that the absorption is really due to these molecules, but must be attributed to some heretofore unidentified absorption process.
Get full access to this article
View all access options for this article.