Electronic Excitation of HgX (X=Cl, Br, I) Due to Electron and Methyl Mercury Halide Collisions

摘要

Electronic excitation of HgX (X = Cl, Br, I) radicals in the B-state has been observed as the result of collisions with low energy electrons and methyl mercury halide (CH3HgX) molecules. The emission intensity has been observed to be much weaker than that observed for electron-HgX2 collisions under similar experimental conditions. Using the strongest band head of the B-X band system, an attempt has been made to calculate the emission cross section due to electron CH3HgX collisions at 10 eV electron kinetic energy. For HgCl, HgBr, and HgI radicals, these cross section are 1 x 10 to the -18th, 7 x 10 to the 17th, and 2 x 10 to the -17th sq. cm., respectively, with an estimated uncertainty of + or - 30%. Our measured threshold electron energy for excitation of CH3HgX molecules and observation of the B-X emission band system and emission cross sections measured at 10 eV are greatly different from those measured by Allision and Zare.