Electron transfer, diabatic couplings, and vibronic energy gaps in a phase space electronic structure framework

We investigate the well-known Shin–Metiu model for an electronic crossing, using both a standard Born–Huang (BH) framework and a novel phase space (PS) electronic Hamiltonian framework. We show that as long as we are not in the strongly nonadiabatic region, a PS framework can obtain a relative error in vibrational energy gap and other vibronic matrix elements that are consistently one order of magnitude smaller than what is found within a BH framework. In line with recent results showing that dynamics on one PS surface can outperform dynamics on one Born–Oppenheimer surface, our results indicate that the same advantages should largely hold for curve crossings and dynamics on two or a handful of electronic surfaces, from which several implications can be surmised as far as the possibility of spin-dependent electron transfer dynamics.