Reaction and fragmentation dynamics of CH₂I₂ induced by UV photoabsorption

Recent studies have revealed interesting dynamics including two-body breakup in CH₂I₂ [1, 2]. Our study is inspired by an experiment at the JRML pumping gaseous CH₂I₂ molecules with a 266 nm UV laser pulse and measuring the resulting dynamics using Coulomb explosion induced by an intesnse 800 nm probe pulse. Various reaction channels are found such as photodissociation and photoionization, and a transient isomerization pathway is predicted but not conclusively detected before [3]. We calculate the potential energy surfaces of CH₂I₂ and CH₂I₂⁺ using post Hartree-Fock methods, based on which we study the reaction dynamics of the molecules. We discuss the two-body and three-body dissociation and the photoionization processes, and compare them to the Coulomb explosion images, focusing on the direct intra-molecular isomerization mechanism.

[1] Yusong Liu et al, Phys. Rev. X, 10, 021016 (2020)

[2] Veniamin A. Borin et al, Phys. Chem. Chem. Phys., 18, 28883 (2016)

[3] B. Kaderiya, Y. Ding, F. Ziaee, E. Wang, K. Borne, S. Bhattacharyya, N. Marshall, T. Severt, Kanaka Raju P., I. Ben-Itzhak, B. Esry, L. Greenman, D. Rolles. A. Rudenko, (unpublished)