Elastic and elastic integer total cross-sections (including elastic and charge transfer cross-sections) for He⁺(1s)−He(1s²) collisions and comparison with previous theoretical date(Barata & Conde 2010; Chicheportiche et al. 2013). Black solid line: elastic cross-sections calculated by Eq. (6a). Red solid line: elastic integer total cross-sections calculated by Eq. (9). Blue solid line: summation of resonant charge transfer cross-sections calculated by Eq. (7) and elastic cross-sections calculated by Eq. (6a).