A measurement of the photoionization cross section of CH2Cl via photofragment translational spectroscopy of dichloromethane

Abstract We characterize the 157 nm photodissociation of dichloromethane (CH 2 Cl 2 ) using photofragment translational spectroscopy, detecting the products with photoionization mass spectrometry. The major photodissociation products are Cl + CH 2 Cl and HCl + CHCl. Comparing the integrated ion signal at m/e  = 35 (Cl + ) and m/e  = 49 (CH 2 Cl + ) gives the partial photoionization cross section of CH 2 Cl to parent ion to be σ = 26.6 Mb at 13.7 eV. This value is a quantitative anchor point of the energy-dependent photoionization cross section. In recent work we used this result to quantify the product branching to HCO + CH 2 Cl in the photodissociation of 2-chloroacetaldehyde.