energy. Due to the isotropicity of the random velocity assignment, we have always obtained the states with sufficiently low total angular momentum which collapsed to single-core states rather than to binaries [@grv].

To implement the reflective boundary condition, at each time step the normal components $v_{\perp}$ of the velocities of all particles which had escaped from the container were reversed. Values of the normal components were stored to evaluate the pressure on the wall $P$. $$\label{P}
P(t)=\frac{\sum_{t'=t-t''/2}^{t'=t+t''/2}v_{\perp}(t')}{2\pi R^2 t''}$$

During each simulation run we measured such characteristics as the kinetic energy $\e_{k in}=\frac{3}{2\b}$, the virial variable $\s$ (dimension of energy) quantifying deviations from the virial theorem, $\s \equiv \e +  \e_{kin} -\frac{3 PV R}{N^2}$ (where $P$ is the pressure on the wall, $V=4\pi R^3/3$ is volume of the container, and the factor $N^2/R$ rescales the volume-pressure term to the unit of energy introduced in (\[def\])), ratio of the velocity moments, $ \frac{19 \langle v^2 \rangle ^2}{
5 \langle v^4 \rangle }$ (which should be 1 for the Maxwell distribution), and the number of particles in the core $N_c$ of the prescribed radius $x_c$. For the last measurement we count the number of particles $N_i$ that are within $x_c$ from the 