Quantum Monte Carlo study of the H- impurity in small helium clusters

We report ground state energies and structural properties for small helium clusters (4He) containing a H- impurity computed by means of variational and diffusion Monte Carlo methods. Except for 4He2H- that has a noticeable contribution from collinear geometries where the H- impurity lies between the two 4He atoms, our results show that 4HeNH- clusters have a compact 4HeN subsystem that binds the H- impurity on its surface. The results for N≥3 can be interpreted invoking the different features of the minima of the He-He and He-H- interaction potentials. © 2000 American Institute of Physics.