  The low-temperature phase diagram of parahydrogen in one dimension is studied
by quantum Monte Carlo simulations, whose results are interpreted within the
framework of Luttinger liquid theory. We show that, contrary to what was
claimed in a previous study [Phys. Rev. Lett. 85, 2348 (2000)], the equilibrium
phase is a crystal. The phase diagram mimics that of parahydrogen in two
dimensions, with a single quasicrystaline phase and no quantum phase
transition; i.e., it is qualitatively different from that of Helium-four in one
dimension.
