Comment on "Sticking of Hydrogen on Supported and Suspended Graphene at   Low Temperature"
  The sticking probability of cold atomic hydrogen on suspended graphene calculated by Lepetit and Jackson [Phys. Rev. Lett. {\bf 107}, 236102 (2011)] does not include the effect of fluctuations from low-frequency vibrations of graphene. These fluctuations suppress the sticking probability for low incident energies ($\lesssim 15$ meV). 
Dennis P. Clougherty
cond-mat.mes-hall cond-mat.mtrl-sci