GROUND STATE $\tilde{X}^{2} A^{\prime}$ DYNAMICS OF THE VINYL AND $d_{2}$-VINYL RADICALS UPON EXCITATION TO THE $\tilde{X}^{2} A^{\prime\prime}$ STATE.

Abstract

Excitation of vinyl radical to the $\tilde{A}$ state leads to the dissociation of vinyl radical via internal conversion into highly excited vibrational levels of the $\tilde{X}$ state. This was used as a method of energy deposition above the dissociation barrier of the $\tilde{X}$ state. Velocity maps of H and D atoms that are products of $CH_{2}=CH$ and $CD_{2}=CH$ dissociation accompanied by acetylene, were measured in the excitation energy range $E \approx 6750 - 9150 cm^{-1}$ above the dissociation barrier of the X state. Rovibrational energy dependencies on the excitation energy, E, inferred for acetylene and $d_{1}$-acetylene products are compared with theoretically predicted ones. An upper limit of $1.3.10^{11} s^{-1}$ is derived for the rate constant of H-atom scrambling between the $\alpha$ and $\beta$ carbon atoms.