  In this paper [published in Phys. Rev. E 102, 042210 (2020)], a new method
for the calculation of excited chaotic eigenfunctions in arbitrary energy
windows is presented. We demonstrate the feasibility of using wavefunctions
localized on unstable periodic orbits as efficient basis sets for this task in
classically chaotic systems. The number of required localized wavefunctions is
only of the order of the ratio t H /t E , with t H the Heisenberg time and t E
the Ehrenfest time. As an illustration, we present convincing results for a
coupled two-dimensional quartic oscillator with chaotic dynamics.
