Investigation of collisional quenching of CCl2 ((A)over-tilde(1)B(1)) in different vibrational states

CCl2 free radicals were produced by a pulsed dc discharge of CCl4 (in Ar). Ground eletronic state CCl2 (X) radicals were electronically excited to, (A ) over tilde B-1(1) (0,3,0), (0,4,0), (1,3,0), (0,6,0), (1,4,0), and (2,2,0 ) vibronic states by a Nd:YAG laser pumped dye laser at 550.56, 541.52, 532 .25, 524.31, 523.82, and 523.37 nm, respectively, Experimental quenching da ta of excited CCl2((A) over tilde B-1(1) and (a) over tilde B-3(1)) by CH3O H, C2H5OH, n-C3H7OH, n-C4H9OH, CH2Br2, CH3COCH3, CH3COC2H5, NH(CH3)(2), NH( C2H5)(2), N(C2H5)(3), and n-C6H14 molecules were obtained by observing the time-resolved total laser induced fluorescence(LIF) signal of the excited C Cl2 radical, which showed a superposition of two exponential components und er the presence of quencher. The quenching rate constants of the (A) over t ilde(B-1(1)) and (a) over tilde(B-3(1)) states Of CCl2, k(A) and k(a), were derived by analyzing the experimental data according to a proposed three-l evel-model to deal with the CCl2 ((X) over tilde (1)A(1), (A) over tilde B- 1(1), (a) over tilde B-3(1)) system. It is found that the total collisional quenching rate constants Of CCl2 (A) over tilde B-1(1) are independent of its vibronic states for a given collisional partner.