Vacuum ultraviolet laser pulsed field ionization-photoelectron study of allyl radical CH₂CHCH₂

The pulsed field ionization-photoelectron PFI-PE spectrum of allyl radical CH₂CHCH₂ (C₃H₅) in the energy range of 65 200–66 600 cm⁻¹ has been measured using vacuum ultraviolet laser. Based on the simulation of the rotational structures resolved in the vibrational PFI-PE bands of C₃H₅⁺(X̃¹A₁;0⁰⁺ and v₇⁺=1), the ionization energies IEs of C₃H₅(X̃²A₂;0⁰) to form C₃H₅⁺(X̃¹A₁;0⁰⁺ and v₇⁺=1) are determined to be 65584.6±2.0 cm⁻¹ (8.13146±0.00025 eV) and 66020.9±2.0 cm⁻¹ (8.18556±0.00025 eV), respectively, where v₇⁺(a₁) is the symmetric C–C–C bending mode of C₃H₅⁺(X̃¹A₁). These values are compared to IEC₃H₅ values obtained in previous experimental and high-level ab initio quantum theoretical studies. © 2007 American Institute of Physics.