An infinite set of one-range addition theorems without an infinite second series, for Slater orbitals and it derivatives, applicable more than one coordinate system

TL;DR

This paper introduces a new set of addition theorems for Slater orbitals that are applicable in multiple coordinate systems and have a finite second series, simplifying quantum amplitude calculations.

Contribution

The authors derive an infinite set of one-range addition theorems with a finite second series, applicable to multiple coordinate systems, improving upon previous theorems.

Findings

Applicable to more than one coordinate system

Retain one-range variable dependence

Useful for Yukawa-like functions in integral reduction

Abstract

Addition theorems have been indispensable tools for the reduction of quantum transition amplitudes. They are normally utilized at the start of the process to move the angular dependence within plane waves and Coulomb potentials, and the like, into a sum over Spherical Harmonics that allows the angular integration to be carried out. These have historically been ``two-range'' addition theorems, characterized by the two-fold notation $r_{>}=Max[r_{1},r_{2}]$ and $r_{<}=Min[r_{1},r_{2}]$ and comprising a single infinite series. More recently, ``one-range'' addition theorems have been created that have no such piecewise notation, but at the cost of a second infinite series. We use a very different approach to derive an infinite set of addition theorems for Slater orbitals and its derivatives that retain the one-range variable dependence but have, at worst, a finite second series rather than an infinite one. Also unlike previous addition theorems, they are applicable to more than one coordinate system. One of these addition theorem may also be used for Yukawa-like functions that may appear late in the reduction of amplitude integrals and we show its utility for an integral that has stubbornly defied reduction to analytic form for nearly sixty years.