The number of degrees of freedom 3 N(z j ) should be adjusted to account for fixing the total momentum of the entire system, by subtracting 3 in total, but distributed over the entire temperature profile. Since 50 bins were typically used, we would need to subtract approximately 3/50 = 0.06 from the number of degrees of freedom in each bin. As the number of degrees of freedom was typically 3 • 1200/50 = 72 in each bin with N(z j ) ≈ N/N bins = 1200/50, the adjustment would have been on the order of 0.1 % and thus negligible. In this context, we investigated the influence of system size (i.e., the number of molecules) on the Soret coefficient-and thus on the temperature profile-while keeping the number of bins constant, and found no measurable influence when using larger systems, in agreement with previous work. Usually, four different temperature differences ∆T between the region of high T high and low temperature T low were considered. The relative imposed temperature differences (T high -T low )/(0.5 • (T high + T low )) were set to 13.3 %, 26.6 %, 40%, and 53.3 %, respectively. The largest temperature gradient observed in the simulations was 0.026 such that violation of local equilibrium is not expected. After a certain response time, a steady state was observed, where the temperature gradient induced a mole fraction gradient. The simulation time of 3500 to 5000 Lennard-Jones units spent to establish the steady state was selected based on transient density profiles reported by Bonella et al. The mole fraction of component k in bin j x k (z j ) was calculated as the ratio of the number of molecules of component k in bin j N k (z j ) over the total number of molecules in bin j N(z j )