Ab initio structures and stabilities of helide cations: HeXn+ (X = B-Ne, Al-Ar and n = 1-3) J. M. Hughes and E. I. von Nagy-Felsobuki Eur. Phys. J. D, 6 2 (1999) 185-192 Published online: 15 May 1999 DOI: 10.1007/s100530050300