Self-assembling of the neutral intermediate with chemically bound argon in photoexcited van der Waals complex Ar-I.

Photodissociation of the van der Waals complex Ar-I after excitation into the Rydberg states of I has been investigated with velocity map imaging of photofragments. Formation of the translationally hot ions of argon Ar with three modes in kinetic energy distribution has been revealed. The measured dependence of the kinetic energy of Ar on the pumping photon energy indicates the appearance of Ar from three channels of the photodissociation of the linear intermediate Ar-I-I containing chemically bound argon. These channels are (1) dissociation into Ar+ I ; (2) three-body dissociation into (Ar)* + I* + I, with (Ar)* and I* being the P states of the species; and (3) two-body electron photodetachment, giving rise to Ar + I + e. Three indicated channels are similar to those established for the photodissociation of trihalide anions. This similarity confirms the conclusion on the formation of the Ar-I-I intermediate, which is isoelectronic to the trihalide anion Cl-I-I. The mechanism of the Ar-I-I formation involves two-photon excitation of the complex Ar-I into the Rydberg state of I converted into the ion-pair state and further electron transfer from Ar to I of the ion-pair state. The self-assembling of the structure making the formation of the Ar-I-I intermediate energetically accessible is confirmed by modeling the dynamics in the excited linear complex Ar-I. Photoexcitation of the van der Waals complexes of noble gases with halogens into the ion-pair states of halogen is supposed to be a promising approach for generating the new chemical compounds of noble gas atoms.