  Population of the 8 eV $^{229m}$Th isomer via the second nuclear excited
state at 29.19 keV by means of coherent x-ray pulses is investigated
theoretically. We focus on two nuclear coherent population transfer schemes
using partially overlapping x-ray pulses known from quantum optics: stimulated
Raman adiabatic passage (STIRAP), and successive $\pi$ pulses. Numerical
results are presented for three possible experimental setups. Our results
identify the Gamma Factory as the most promising scenario, where two
ultraviolet pulses combined with relativistically accelerated ions deliver the
required intensities for efficient isomer population. Our simulations require
knowledge of the in-band and cross-band nuclear transition probabilities. We
give theoretically predicted values for the latter and discuss them in the
context of recent experiments.
