Localization of Spherical Harmonic Expansions.
The paper focuses on a low-rank tensor structured representation of Slater-type and Hydrogen-like orbital basis functions that can be used in electronic structure calculations. Standard packages use the Gaussian-type basis functions which allow us to analytically evaluate the necessary integrals. Slater-type and Hydrogen-like orbital functions are physically more appropriate, but they are not analytically integrable. A numerical integration is too expensive when using the standard discretization...
S. K. Chatterjea has recently proved a class of generating relations involving ultraspherical polynomials from the view point of continuous transformations-groups. The object of the present paper is to point out that this class of generating relations implies the explicit representation, the addition and the multiplication formulas, in addition to the usual generating relation for the ultraspherical polynomials.
The polynomial functions on a projective space over a field = ℝ, ℂ or ℍ come from the corresponding sphere via the Hopf fibration. The main theorem states that every polynomial function ϕ(x) of degree d is a linear combination of “elementary” functions .