Collisional redistribution of radiatively-excited levels of Tl and Ga atoms in an O2-acetylene-Ar flame

Several useful expressions for the population ratios of collisionally excited levels have been derived and different transitions of Tl and Ga atoms, seeded in a premixed atmospheric flame, have been excited in order to verify that the levels higher than the laser-excited level are populated approximately according to a Boltzmann equilibrium. This result confirms the possibility of using thermally assisted flourescence lines to measure local temperatures in flames. The Einstein spontaneous emission probability for the transition 6S_1/2→4P_3/2 at 2719.65Å of Ga has also been calculated (A_2719.65=0.41×10⁸s^-1) to fit the experimental point.