Shock tube studies on the radical emission spectra by use of an imaging spectrometer.

Abstract

The emission spectrum of OH (A²Σ⁺-X²Π) and SiH (A²Δ-X²Π) have been studied behind reflected shock waves. A piston-driven shock tube has been used to get a good reproducibility of the shock heated conditions and the spectrum have been obtained by the computerprocessed imaging spectrometer. The vibrational temperatures of OH (A²Σ⁺) are found to be in equilibrium with the shock temperatures over 2800 to 4000 K in the test gas of 3.3% H₂ +1.7% O₂+Ar. It is also found that the addition of small amount of NO (2-4%) to SiH₄+Ar mixtures has caused drastic suppression of SiH (A²Δ-X²Π) emissions at high temperatures of 2500 to 4400 K. The mechanism of the quenching of SiH by addition of NO is discussed.