Knowledge Bank

Vibrationally excited $CH3Cl$ is prepared by laser excitation in the fourth overtone C-H stretch band near 725 nm photodissociated al fixed wavelengths near 240 nm which also probe either The H, Cl($\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}P3/2$), or Cl($\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}P1/2$) photofragments via (2+1) resonance enhanced multiphoton ionization (REMPI) in a time-of-flight mass spectrometer. Jet cooling of the $CH3Cl$ reveals two partially resolved bands in the overtone excitation spectrum which are assigned to [5,0,0] and $[4,0,0]+2\nu 2$. The product yields from the photolysis of vibrationally excited $CH3Cl$ show decided enhancement compared to photolysis of the ground state. Branching ratios of atomic products are also determined for photolysis of both excited and ground state $CH3Cl$. The ratio of Cl($\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}P1/2$) to Cl($\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}P3/2$) is dramatically larger for photolysis of vibrationally excited vs. ground state $CH3Cl$.