Hash vacuum photolysis

The Br(2P1/2) state lies 0.456 eV above the ground 2P3/2 state and is meta-stable with a lifetime of 1.12 sec. The Br(2P,/2) atoms can be detected by absorption at 1532, 1582, and 1634 A. The Hash photolysis in the vacuum ultraviolet of HBr, Br2, CHCl2Br, and CF3Br has produced Br(2P,/2) atoms that have been observed by optical absorption [Donovan and Husain (299)]. The quenching efficiency of Br(2P1/2) produced from the Hash photolysis of CF3Br by various gases has been studied by Donovan and Husain (300). 

Donovan and Husain (299) have detected Br(2/>,/2) in the vacuum ultraviolet Hash photolysis of CHCI2Br and CF,Br but not from CHjBr and CH2Br2. 

Noxon calculated the rate constant of O( D) quenching by 02 on the basis of unit quantum yield and of the equilibrium concentration of 0( >) atoms. His value of 6 x 10 11 cm3 molec"1 sec-1 agrees well with 7 x 10"11 cm3 molec"1 sec" 1 obtained independently (456), indicating that the assumption of unit quantum yield may be justified. Below 1332 A the production of O( S) is energetically possible. Filseth and Welge (348) have observed an emission at 5577 A due to the transition O( S)- O( D) in the flash photolysis of 02 below 1340 A. The intensity is so weak that Xe has to be added to induce the transition. No quantum yield of O(. S) production has been measured. Recently Stone et al. (937) have measured the llight time ofO atoms produced in the Hash photolysis of the molecular beam of 02 in the vacuum ultraviolet. The O atoms are detected by the chcmiionization reaction with samarium. The technique is similar to the one described in Section II 4.1. 

The Hash photolysis of CH2N2 in the near and vacuum ulll.l l resulis in the production of the singlet CH2 [Herzberg and John-. 1 r Her/.berg (464), Braun et al, (143)],... 

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