  The recent development of multidimensional ultrafast spectroscopy techniques
calls for the introduction of computational schemes that allow for the
simulation of such experiments and the interpretation of the corresponding
results from a microscopic point of view. In this work, we present a general
and efficient first-principles scheme to compute two-dimensional electronic
spectroscopy maps based on real-time time-dependent density-functional theory.
The interface of this approach with the Ehrenfest scheme for molecular dynamics
enables the inclusion of vibronic effects in the calculations based on a
classical treatment of the nuclei. The computational complexity of the
simulations is reduced by the application of numerical advances such as
branching techniques, undersampling, and a novel reduced phase cycling scheme,
applicable for systems with inversion symmetry. We demonstrate the
effectiveness of this method by applying it to prototypical molecules such as
benzene, pyridine, and pyrene. We discuss the role of the approximations that
inevitably enter the adopted theoretical framework and set the stage for
further extensions of the proposed method to more realistic systems.
