Excitation dynamics involving homogeneous multistate interactions: one and two color VMI and REMPI of HBr

Abstract

Velocity map imaging (VMI) data and mass resolved REMPI spectra are complementarily utilized to elucidate the involvement of homogeneous multistate interactions in excited state dynamics of HBr. The H¹Σ⁺(v′ = 0) and E¹Σ⁺(v′ = 1) Rydberg states and the V¹Σ⁺(v′= m + 7) and V¹Σ⁺(v′= m + 8) ion-pair states are explored as a function of rotational quantum number in the two-photon excitation region of 79 100–80 700 cm⁻¹. H⁺ and Br⁺ images were recorded by one- as well as two-color excitation schemes. Kinetic energy release (KER) spectra and angular distributions were extracted from the data. Strong-to-medium interactions between the E(1) and V(m + 8)/V(m + 7) states on one hand and the H(0) and V(m + 7)/V(m + 8) states on the other hand were quantified from peak shifts and intensity analysis of REMPI spectra. The effects of those interactions on subsequent photoionization and photolytic pathways of HBr were evaluated in one-color VMI experiments of the H⁺ and two-color VMI experiments of the Br⁺ photoproducts.