engleski

Diffusion Monte Carlo study of the small mixed He-3-He-4 clusters

The ground state properties of helium mixed clusters $^3$He$_{; ; ; 2, 3, 4}; ; ; $$^4$He$_2$, $^3$He$_{; ; ; 2, 3, 4}; ; ; $$^4$He$_3$, $^3$He$_{; ; ; 2, 3, 4}; ; ; $$^4$He$_4$, $^3$He$_{; ; ; 2, 3}; ; ; $$^4$He$_5$, consisting of up to eight helium atoms are studied using variational and diffusion Monte Carlo calculations. For clusters with three and four $^3$He atoms released-node diffusion Monte Carlo method is used. Our calculations show that, within errorbars, clusters $^3$He$_{; ; ; 3, 4}; ; ; $$^4$He$_2$ have the same binding energy as the cluster $^3$He$_2$$^4$He$_2$, and that $^3$He$_3$$^4$He$_3$ has the same binding energy as $^3$He$_2$$^4$He$_3$. The clusters $^3$He$_{; ; ; 3, 4}; ; ; $$^4$He$_2$ and $^3$He$_3$$^4$He$_3$ are in states in which one or two $^3$He atoms are far away from the rest of the system. Other considered clusters are bound. In particular, we have shown the stability of the cluster $^3$He$_4$$^4$He$_3$, which was previously considered unstable. The calculations are performed using several different interatomic potentials and the conclusions concerning stability are insensitive to the particular form of the interaction potential. We compare our results with the recent experiment and other theoretical calculations.

3He-4He mixed clusters; stability; ground state; diffusion Monte Carlo

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