Premium
Chemical lasers produced from O( 3 P ) atom reactions. III. 5‐μm CO laser emission from the O + CH reaction
Author(s) -
Lin M. C.
Publication year - 1974
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550060102
Subject(s) - chemistry , laser , excited state , analytical chemistry (journal) , ultraviolet , population , diluent , atomic physics , optics , nuclear chemistry , physics , demography , chromatography , sociology
Very strong laser emission at 5 μm was detected when SO 2 and CHBr 3 were flash photolyzed in the vacuum ultraviolet (λ ≥ 165 nm) in the presence of a large amount of diluent (SF 6 , He, or Ar). About 110 vibration–rotation transitions ranging from Δ v = 18 → 17 to 3 → 2, except 16 → 15, were identified. The primary reactions leading to the CO stimulated emission are as follows:The product analysis results and the variation of laser intensity with flash energy and SO concentration indicate that the following side reactionsare also occurring. Addition of a small amount of O 2 enhances the laser output by both eliminating these side reactions and simultaneously producing vibrationally excited CO via reaction (8),which has been previously shown to generate CO stimulated emission. The effects of various reactive (NO and H 2 ) and inert (He, Ar, SF 6 , CO, N 2 , N 2 O, and CO 2 ) gases have been examined. All additives ( P ≤ 20 torr), except NO and H 2 , increase the total laser output. N 2 O enhances the power most efficiently, whereas CO, N 2 , and CO 2 are less effective and have similar efficiencies. The enhancement of the laser intensity by these near‐resonant gases is ascribed to the depletion of CO population at lower levels which thus increases the rates cascading from higher levels. NO and H 2 quench the laser output by chemically reducing the concentration of the CH radical.