Acetylenic C-H and methyl C-D bond fission in photodissociation of vibrationally excited propyne-d 3 Academic Article uri icon


  • Vibrational preexcitation of a state containing three quanta of C–H stretch (3ν 1) results in C– H acetylenic and C–D methyl bond rupture in the∼ 243.1 nm photolysis of CD 3 C≡ CH, in contrast to previous observations of the almost isoenergetic 193 nm photodissociation of propynes. The C–D bond fission is the dominant pathway with a D/H branching ratio of 2.0±0.5 at a combined energy of∼ 50 830 cm− 1. The average translational energies of D and H atoms are nearly identical, although the C–H acetylenic and C–D methyl bond energies differ quite extensively, pointing to different dynamics on the involved potential energy surfaces.

publication date

  • October 1, 2000