Collisional quenching of Ga(5p) atoms by H2, D2 and CH4

Collisional quenching of Ga(5p) atoms by H2, D2 and CH4 has been studied. The gallium atoms were generated by photolysis of trimethyl gallium using a KrF laser. The Ga(5p) state was populated by two-photon excitation from the ground state and cascade fluorescence from Ga(5s) atoms was analyzed to extract quenching rate constants for Ga(5p) atoms. The apparent quenching rate constants for Ga(5p) atoms are (4.6±0.3)×10−10, (3.4±0.3)×10−10 and (7.8±0.2)×10−11 cm3 molecule−1 s−1 by H2, D2 and CH4, respectively. It is found that the predominant process for the large quenching rate constants for Ga(5p) atoms by H2 and D2 is the energy transfer for Ga(5s) formation.