LAUSR

We present the frequency-dependent geminal-screened electron-hole interaction kernel (FD-GSIK) method for describing electron-hole correlation in electronically excited many-electron systems. The FD-GSIK is a parameter-free, first-principle method which was derived from excited state wavefunction that was both frequency-dependent and r12-explicitly correlated. The FD-GSIK avoids using unoccupied orbitals for kernel construction by performing infinite-order summation of particle-hole excitation and representing it as a compact real-space operator. It bypasses the computational demanding steps of evaluation, storage, and transformation of atomic-orbital integrals by evaluating molecular orbital integrals directly in real space using stratified Monte Carlo method. We demonstrate and discuss the advantages of this method by presenting excitation and electron-hole binding energies of large nanoparticles including Pb140S140, Pb140Se140, Cd144Se144, and Cd72S72.