文摘
Iodine monobromide (IBr) and its cation (IBr+), which play an important role in the stratospheric ozone depletion, have received much attention. However, the electronic states of IBr/IBr+ have not been well understood. In this paper, the potential energy curves (PECs) of low-lying electronic states for IBr/IBr+ were computed with high-level multireference configuration interaction (MRCI) method. The spin-orbit coupling effect was taken into account via the state interaction method with the full Breit-Pauli Hamiltonian. For IBr, the PECs of 12 螞-S states correlated with the lowest dissociation limit of IBr molecule and 23惟 states generated from those 螞-S states were calculated. The spectroscopic constants of the bound states were obtained, which are consistent with previous experimental results. The two avoided crossing points between (2)0+/(3)0+ and (3)0+/(4)0+ were interpreted by analysis of 螞-S compositions of 惟 states at various bond lengths. Based on potential energy curves and transition dipole moments, the radiative lifetime of 13螤1 was evaluated. For IBr+, the PECs of 12 螞-S states and 4 low-lying 惟 states were calculated, from which the spectroscopic constants were evaluated. Finally, the ionization energies from the neutral ground state (X1危+) to different ionic states (X2螤3/2, X2螤1/2, A2螤3/2 and A2螤1/2) were obtained.