For all systems, an initial minimization was performed using the steepest descent algorithm. A constant temperature corresponding to the reference experimental setup was maintained implicitly using the leap-frog stochastic dynamics integrator 115 with an inverse friction constant of γ = 0.5 ps -1 . Pressure was maintained at 1 bar using the Parrinello-Rahman barostat 116 with a coupling time constant of 5 ps. The simulation time step was set to 2 fs. Long-range electrostatic interactions were calculated using the Particlemesh Ewald method 117 with a real-space cutoff of 1.2 nm and a Fourier spacing of 0.12 nm. Lennard-Jones interactions were force-switched off between 1.0 and 1.2 nm. Bonds to hydrogen atoms were constrained using the Parallel LINear Constraint Solver 118 .