Study on the role of the cool body for the enhancement of sulphur diatomicmolecular emission in a hydrogen flame with a multi-channel spectral analyser

Change in the emission spectrum of diatomic sulphur molecule derived from a sulphur containing compounds in a hydrogen flame is measured with a multi- channel spectral analyser. The emission appears with introducing a cool bod y to the flame. The intensity decreases with time, while temperature of the body increases. It is expected that the introduction of a cool body to a f lame suppresses the pre-dissociation of the excited diatomic sulphur molecu les by collisional de-activation, and the possibility is discussed. Since t he ratio of the number of molecule in the v' = 1 to that in the v' = 0 incr eases with increasing the ambient temperature near the body, it is conclude d that the excited sulphur molecules are deactivated by collision with othe r molecules to the lower vibrational levels in the excited state. But, it i s also noted that the collisional deactivation occurs even without the cool body and the S-2 emission from a CS2 flame is not enhanced with the cool b ody. It is concluded that the enhancement effect observed in a hydrogen fla me is not attributed to the suppression on the pre-dissociation of the exci ted molecules. (C) 2001 Elsevier Science B.V. All rights reserved.