A configurational study of helium clusters doped with He∗− and He2∗−

9 pags.; 10 figs.; 4 tabs.Helium clusters doped with electronically excited atomic and molecular helium anions He∗− and He∗−\ud2 at T = 0.4 K are studied by means of path integral Monte Carlo calculations. Geometry and energetics\udof the systems with up to 32 solvating He atoms are characterised. The interactions between the\udanions and the neutral He atoms have been described by fitting previously reported ab initio points to\udanalytical expressions. The HeN–He∗− clusters with N > 6 display a structure defined by a bipyramid\udwhich completely solvates the atomic anion, whereas the rest of surrounding He atoms form a dimple\udaround that initial cage. On the contrary, the structures observed for the HeN–He∗−2 clusters clearly\udshow the dopant located outside the helium droplet, thereby confirming the heliophobic character of\udHe∗− 2. C 2015 AIP Publishing LLCThis work has been supported by MICINN Grant No.\udFIS2011-29596-C02-01. R.R.-C. acknowledges funding from\udGrant No. JAE-Pre-2010-01277. F.A.G. acknowledges several\udhelpful discussions with A. Mauracher and thanks him for\udproviding us with the original computed ab initio points for\udthe He–dopant interactionsPeer Reviewe