Oxygen-assisted excitation of methyl iodide as a test of double spin-flip transition in van der Waals complex CH₃I-O₂

Photoexcitation of van der Waals (vdW) complex CH₃I-O₂ has been studied with velocity map imaging of I atoms arising in photodissociation. A new scheme of resonance-enhanced multiphoton ionization of iodine atoms has been applied with simultaneous use of UV and VIS radiation. The measured kinetic energy of I(²P_3/2) atoms indicates photogeneration of precursor CH₃I molecules via complex-specific channel with excitation energy expected for double spin-flip transition in complex CH₃I-O₂. The angular distribution for recoil directions of I(²P_3/2) atoms coming from vdW complexes also corresponds to that expected for double spin-flip transition.