State-to-state correlated study of $CD3I$ photodissociation at 266 and $304nm$

High-resolution photofragment translational spectroscopy is used in this work to measure the translational and internal energy distributions in the $CD3$ and iodine fragments produced from the photodissociation of $CD3I$ at 266 and $304nm$⁠. Channel selected detection, via resonantly enhanced multiphoton ionization, combined with one-dimensional core sampling provides detailed information about vibrational state distributions of the $CD3$ fragments. The vibrational state distributions of $CD3$ fragments in the $I*(P1∕22)$ channel have a propensity of $ν2′$ umbrella bending mode with a maximum at $ν2′=1$ for $266nm$ photodissociation. For $I*(P1∕22)$ channel at $304nm$ photodissociation, vibrational state distributions of $CD3$ fragment have a maximum in the vibrational ground state. For the $I(P3∕22)$ channel $(Q11←Q0+3)$⁠, $ν2′$ umbrella bending vibrational distribution is measured as the predominant vibrational mode but has a much broader distribution when compared to that of the $I*$ channel. The vibrational state distributions of the $CD3$ fragment produced from the perpendicular transition, i.e., $Q13$⁠, which was determined at $304nm$ photodissociation, has a maximum at $ν2′=1$⁠. The curve crossing possibility between the $Q11$ and $Q0+3$ adiabatic potentials is determined as 0.19 for 266 and 0.85 for $304nm$⁠. The trend in reaction dynamics in 266 and $304nm$ photodissociation of $CD3I$ is compared with theoretical calculations. A bond dissociation energy $D0(C–I)=56.60±0.5kcal∕mol$ was derived by applying laws of energy conservation.