In addition to for atomic degrees of freedom, also
the friction coefficient for lattice degrees of freedom has to be defined
in the case of Parrinello-Rahman dynamics [79,80] (see 6.62.6):
LANGEVIN_GAMMA_L=[real] friction coefficients (in ps) for lattice
degrees of freedom
Note that Langevin dynamics with set to zero is equivalent to deterministic ( in the case of Parrinello-Rahman method) dynamics.