Figure 1

(Color online) (a) Nonequilibrium molecular dynamics of isentropic release waves. The four pictures represent snapshots of slices of the system in the $\left(x,y\right)$ plane during the release process, the expansion proceeding in the longitudinal $x$ direction. Atoms are colored according to their potential energies (scaling corresponding to $-1.38\times {10}^{-20}\text{J}$ for blue up to $7.55\times {10}^{-20}\text{J}$ for red). (b) Density profiles taken at different times of the simulation. The slope at the ends of the system are less steep as time advances.Reuse & Permissions

Figure 2

Path in the $\left({\lambda }_1,{\lambda }_2\right)$ space used to compute states with the same entropy as the pole. Each cross represents some equilibrium canonical sampling along the thermodynamic path. First, the isothermal expansion is performed (horizontal line in the diagram), starting from the pole (0, 0), until the required density is reached. The entropy of the state $\left({\lambda }_1,0\right)$ is $S_{\text{pole}}+\Delta S_{\text{expansion}}$. Then, an isochore cooling is performed (${\lambda }_1$ is kept fixed; vertical line in the diagram), until the entropy difference during this process is the opposite of the entropy variation found in the expansion part. The final state $\left({\lambda }_1,{\lambda }_2\right)$, located at the intersection of the curve $\Delta S=0$ and the vertical line, has then the same entropy as the pole.Reuse & Permissions

Figure 3

(Color online) Isentropic release in a $\left(P,\rho \right)$ diagram. Symbols represent results from equilibrium methods, red diamonds for the successive hugoniostat (“SDLNVHug”), blue squares for the thermodynamic integration (“$\Delta S$”) and yellow triangles for the entropy integration (“$\partial P/\partial E$”). NEMD results are plotted in green, the width of the so-obtained tube corresponding to the error bars. The arrow indicates the path followed during the release.Reuse & Permissions

Figure 4

(Color online) Isentropic release in a $\left(T,P\right)$ diagram. The symbols are the same as in Fig. 3. Notice that there is slight deviation of the NEMD results for the lowest temperatures.Reuse & Permissions

Figure 5

(Color online) Isentropic release in a $\left(T,\rho \right)$ diagram. The symbols are the same as in Fig. 3. There is a noticeable deviation of the NEMD results for the lowest temperatures.Reuse & Permissions