Eur. Phys. J. D (2012) 66: 198
https://doi.org/10.1140/epjd/e2012-30202-6

Regular Article

Binding weakly interacting partners: a study of Ca–He₂ and its isotopomers

¹ Instituto de Física Fundamental,IFF-CSIC, Serrano 123, 28006 Madrid, Spain
² Department of Chemistry and CNISM, University of Rome La Sapienza, Piazzale A. Moro 5, 00185 Rome, Italy

^a e-mail: p.villarreal@iff.csic.es

Received: 27 March 2012
Received in final form: 3 May 2012
Published online: 26 July 2012

Abstract

We present in this paper binding energies and structures of non-rotating weakly bound ⁴⁰Ca–ⁿHe₂ triatomic complexes. Two kind of systems are discussed: bosonic (n = 4) and fermionic (n = 3) complexes at its singlet state (nuclear spin S = 0). Three different coordinate systems and methods have been used to solve the relevant Schrödinger equation: variational calculations (1) using satellite coordinates and a discrete variable representation of radial functions; (2) employing pair coordinates and products of distributed Gaussian functions as basis functions; and (3) variational/Diffusion Monte Carlo calculations in Cartesian coordinates. The potential energy surface is represented as the addition of pair potentials. By using the most realistic interaction between each pair of particles, present results from the three methods are in fair agreement. Only two bound states for each system are found in our computations.