Ab initio potential energy curves of the valence, Rydberg, and ion-pair states of iodine monochloride, ICl

Abstract

Extensive ab initio study of the valence and low-lying Rydberg states of BBr including spin-orbit coupling J. Chem. Phys. 124, 194307 (2006) We present for the first time a coherent ab initio study of 39 states of valence, Rydberg, and ionpair character of the diatomic interhalogen ICl species through large scale multireference variational methods including spin-orbit effects coupled with quantitative basis sets. Various avoided crossings are responsible for a non-adiabatic behaviour creating a wonderful vista for its theoretical description. Our molecular constants are compared with all available experimental data with the aim to assist experimentalists especially in the high energy regime of up to ∼95 000 cm −1 .

Quantum Interference Effects Theoretically Found in the Photodissociation Processes of the Second Absorption Bands of ICl and IBr Molecules

“…32 In general, the nonadiabatic dynamics between these states should be treated by including quantum interference effects with the appropriate phase information taken into consideration; however, for the second absorption bands of IX, such a study has not been carried out except for our recent study. 33 This avoided crossing was also found in a recent electronic structure study by Kalemos and Prosmiti, 34 although a slight difference was found in the position from our previous calculation. 33 As for the second absorption band of IBr, Faist and Bernstein have supposed close energies of the 0 + (III) and 0 + (IV) states 15 by analogy to the corresponding 0 + g states derived from the 3 Π g (2341) and 3 Σ g − (2422) states of I 2 molecule.…”

“…In general, the nonadiabatic dynamics between these states should be treated by including quantum interference effects with the appropriate phase information taken into consideration; however, for the second absorption bands of IX, such a study has not been carried out except for our recent study . This avoided crossing was also found in a recent electronic structure study by Kalemos and Prosmiti, although a slight difference was found in the position from our previous calculation …”