ACETYLENE PHOTOLYSIS AT 1236-A AND 1470-A

To investigate the dependence of the excitation wavelength on the acetylene photolysis, the experiments both at 1236 and 1470 Å were carried out. The systems in the present work were acetylene, acetylene-hydrogen, acetylene-rare gases, acetylene-nitrogen, and acetylene-methane with and without a small amount of nitric oxide. These results were compared with those obtained previously. It was found that rare gases, nitrogen, and perhaps hydrogen, too, hardly affected the excited state of acetylene. It was found that the ratio ethylene/1,3-butadiene increased in proportion to the reciprocal of the pressure in all systems except acetylene-hydrogen, where the following chain reactions may be contained. C2H2 + H → C2H3‡ C2H3‡ + M → C2H3 C2H3(‡) + H2 → C2H4 + H The ratio k6/k6′ C2H2* + C2H2 →k6 C4H2 + 2H →k6′ C4H2 + H2 seems larger at 1236 than at 1470 Å.