Population and decay of <i>T</i>-shaped ArI2 van der Waals complex ion-pair states studied using two-step, two-color excitation and luminescence spectra measurements

Abstract

Two-step, two-color populations of T-shaped ArI2(E,vE = 0–2,nE) complexes, accompanied by their electronic predissociation, have been studied. The luminescence spectra of the ion-pair I2(IP,vIP), IP = D′2g, β1g, D0u+, molecules, ArI2(E0g+,vE = 0–2,nE) complexes were measured, and the branching ratios of the I2(IP,vIP) populations and ArI2(E,vE = 0–2,nE) lifetimes were determined. The comparison of the spectroscopic characteristics of ArI2(E,vE,nE) complexes obtained in this work and by Macarem and Loomis [Chem. Phys. Lett. 826, 140642 (2023)], has been carried out. Measurements of true luminescence spectra, corrected for the spectral dependence of the registration system sensitivity, allow us to determine the branching coefficients of the population of the vibrational and electronic predissociation products and even their vibrational distributions. In addition, this method allows us to determine the branching ratios of the ArI2(E,vE,nbE,nsE) populations and lifetimes of the complex if its vibrational predissociation is impossible.