Excitons in potassium bromide: A study using embedded time-dependent density functional theory and equation-of-motion coupled cluster methods

We present a study of the lowest surface and bulk excitations of the well-studied potassium bromide (KBr) system using an embedded cluster method. The excited states of the embedded cluster are studied systematically using time-dependent density functional theory (TDDFT) and high-level equation-of-motion coupled cluster (EOMCC) methods. In particular, we have used EOMCC models with singles and doubles (EOMCCSD) and two approaches which account for the effect of triply excited configurations in non-iterative and iterative fashions. We compare and contrast the results between these theories as well as compare our results with experiment. The bulk–surface exciton shift is also calculated at the TDDFT level and compared with experiment.