The very fast chemiluminescent reaction I(5p 52P [formula omitted]) + I(5p 52P [formula omitted]) → (M) I 2(B O u+, υ′) → I 2(X O g+, υ″) + hν

Abstract

The method of quantitative laser induced chemiluminescent kinetic spectroscopy (QLICKS) is developed for the study of chemiluminescence reactions. This method enables us to determine spectral distributions of chemiluminescence rate constants k cl(λ) (photon cm 3/particle 2 s nm) and total chemiluminescence rate constants k cl (photon cm 2/particle 2 s). QLICKS is applied to the study of the iodine atom recombination accompanied by radiation according to I(5p 5 2P 1 2 ) + I(5p 5 2P 3 2 ) → (M) I 2(B O u +, υ′) → I 2(X O g +, υ″) + hν (i). Iodine atoms are obtained by photolysis of RI = CF 3I, CF 3CFICF 3 at λ = 266 nm. Assuming quantum yields of the I( 2P 3 2 ) and I( 2P 1 2 ) atoms formation equal to 0.1 and 0.9, respectively, the following values of the total chemiluminescence rate constant are determined: k i = (10 +10 −5, 7.4 +7 −4 and 3.0 +3 −1.6) × 10 −15 photon cm 3/particle 2 s for M = He, Ar and CF 3CFICF 3 respectively. The rate constant of the process 2I(5p 5 2P 1 2 ) → (M) I 2(1 u) → I 2(1 g) + hν (ii) is estimated to be k ii = (3.5 +3.5 −1.7) × 10 −17 photon cm 3/particle 2 s for M = CF 3I, CF 3CFICF 3. Kinetic and spectral features of reaction (i) can be described only in terms of the I*…M or I…M complex formation. Process (i) may be considered as representative of a wide class of recombination reactions accompanied by radiation proceeding through complex formation with a particle M and having very high rate constants. The existence of such very fast chemiluminescent reactions provides real opportunities for the development of recombination lasers operating on molecular transitions.