1 potential, 2 potentials, 3 potentials–4: Untangling the UV photodissociation spectra of HI and DI

Abstract

A comprehensive empirical analysis based on exact quantum simulations of all available total absorption coefficient and branching-ratio data for the UV photodissociation spectra of HI and DI has been used to determine the potential energy curves of the four excited electronic states A 1 ⌸ 1 , a 3 ⌸ 0 ϩ, a 3 ⌸ 1 , and t 3 ⌺ 1 ϩ , and the associated transition moment functions. It is shown that there is no need to invoke coupling among the various final-state wave functions to explain the data.

Comprehensive ab initio calculation and simulation on the low‐lying electronic states of TlX (X = F, Cl, Br, I, and At)

“…The second kind of transition will generate a continuum spectrum which can be simulated by using the BCONT code 69. The corresponding expression for ε(λ) is documented in ref 70…”

Photoinduced ion-pair formation in the (HI)m(H2O)n cluster system

“…34 This will lead to the rapid dissociation of the HI molecule. 34 This will lead to the rapid dissociation of the HI molecule.…”

The photodissociation of hydrogen iodide: Is it adiabatic?

“…For the three molecules considered in this article (HCl, HBr, and HI), ab initio data for the electronic structure of each of the molecules is used 4, 30, 31. The three empirical models proposed for the PECs and transition dipole moments of HI 2, 16 are not considered. Since the primary purpose of this article is to explore the assumption of adiabatic dissociation, the overall conclusions are not affected by the model chosen for the electronic structure of HI—all recent models assume that the dissociation proceeds adiabatically.…”

“…The photodissociation of hydrogen iodide has been the subject of many experimental and theoretical studies. The photodissociation process to yield ground state, I( 2 P 3/2 ) ≡ I, and spin‐orbit excited state, I( 2 P 1/2 ) ≡ I*, iodine atoms has been the focus of most studies 1–18. The energy difference between the two product channels for HI is 7,603 cm −1 19.…”

“…Through the determination of these properties, the roles of the multiple electronic states and the possible non‐adiabatic coupling can be determined. For HI, the potential energy curves (PECs) and transition dipole moments have been determined either by ab initio calculations 4, 20–22 or by fitting to experimental data 2, 7, 10, 15, 23–25. For recent dynamics calculations investigating HI photodissociation, non‐adiabatic coupling between the electronic states has not been needed to explain the experimental observations — previous dynamics calculations 10 invoked non‐adiabatic coupling but, subsequently, the experimental β parameter measurements 13 upon which the fit was based were shown to be incorrect.…”