  Calculations in ab initio no-core configuration interaction (NCCI)
approaches, such as the no-core shell model or no-core full configuration
methods, have conventionally been carried out using the harmonic-oscillator
many-body basis. However, the rapid falloff (Gaussian asymptotics) of the
oscillator functions at large radius makes them poorly suited for the
description of the asymptotic properties of the nuclear wave function. We
establish the foundations for carrying out NCCI calculations with an
alternative many-body basis built from Coulomb-Sturmian functions. These
provide a complete, discrete set of functions with a realistic exponential
falloff. We present illustrative NCCI calculations for 6Li with a
Coulomb-Sturmian basis and investigate the center-of-mass separation and
spurious excitations.
