A "spin-flip" modification rectifies these problems, within a tractable computational formalism for which nonadiabatic (derivative) coupling vectors have been formulated and implemented based on analytic gradient theory. SF-TDDFT can be used in surface hopping calculations, as well as simply to locate MECPs with correct topology, including those that involve the ground state. For reasons discussed herein, SF-TDDFT calculations are typically performed using the BH&HLYP functional, and MECPs computed in this way show excellent agreement with multireference benchmarks.