COLLISIONAL QUENCHING OF GA(5P) ATOMS BY H-2, D-2 AND CH4

Collisional quenching of Ga(5p) atoms by H-2, D-2 and CH4 has been stu died. The gallium atoms were generated by photolysis of trimethyl gall ium using a KrF laser. The Ga(5p) state was populated by two-photon ex citation from the ground state and cascade fluorescence from Ga(5s) at oms 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)X 10(-10), (3.4 +/- 0.3)X 10(-10) and (7.8 +/- 0.2)X 10(-11) cm(3) molecule(-1) s(-1) by H-2,D-2 and CH4, respectively. It is found that the predominant process for the large quenching rate constants for Ga( 5p) atoms by H-2 and D-2 is the energy transfer for Ga(5s) formation. (C) 1998 Elsevier Science B.V. All rights reserved.