  The accurate description of doubly-excited states using conventional
electronic structure methods is remarkably challenging, primarily because such
excited states require the inclusion of doubly or higher excited configurations
or the application of multi-reference methods. We present a new approach to
target electronically excited states that feature a double-electron transfer.
Our method uses the equation of motion (EOM) formalism with a pair coupled
cluster doubles (pCCD) reference function, where dynamical correlation is
accounted for by a linearized coupled cluster correction with singles and
doubles (LCCSD). Specifically, our proposed EOM-pCCD-LCCSD model represents a
simplification of the conventional EOM-CCSD approach, where the electron-pair
amplitudes of CCSD are tailored by pCCD. The performance of EOM-pCCD-LCCSD is
assessed for the lowest-lying excited states in CH$^+$ and all-trans polyenes.
In contrast to conventional EOM-CC methods with at most double excitations,
EOM-pCCD-LCCSD predicts the right order of states in polyenes with excitation
energies closest to experiment, outperforming even highly-accurate methods such
as the density matrix renormalization group algorithm.
