Improving quasiparticle second order electron propagator calculations with the spin-component-scaled technique

A simple modification of the quasiparticle second order electron propagator (EP2) method based on the spin-component-scaled technique is proposed. In this new approach, the second order contributions to the self-energy of same and opposite spins are scaled by empirical parameters. Comparison with EP2 and higher order approaches for different sets of molecules reveals that the cost-free spin-component-scaled technique reduces average errors of EP2 up to 51%, thereby increasing its reliability and applicability for the calculation of electron binding energies in molecular systems.