# Maple procedures for the coupling of angular momenta. An up-date of the Racah module

## Description

Abstract An up-date of the Racah module is presented, adopted to Maple 11 and 12, which supports both, algebraic manipulations of expressions from Racah's algebra as well as numerical computations of many functions and symbols from the theory of angular momentum. The functions that are known to the program include the Wigner rotation matrices and n - j symbols, Clebsch-Gordan and Gaunt coefficients, spherical harmonics of various kinds as well as several others. Title of program: RACAH Catalogue Id: ADFV_v10_0 Nature of problem The theories of angular momentum and spherical tensor operators, sometimes known also as Racah's algebra, provide a powerful calculus for studying spin networks and (quantum) many-particle systems. For an efficient use of these theories, however, one requires not only a reliable handling of a large number of algebraic transformations and rules but, more often than not, also a fast access to their standard quantities, such as the Wigner n-j symbols, Clebsch-Gordan coefficients, spherical harmonic ... Versions of this program held in the CPC repository in Mendeley Data ADFV_v1_0; Racah; 10.1016/S0010-4655(97)00032-5 ADFV_v2_0; Racah; 10.1016/S0010-4655(98)00021-6 ADFV_v3_0; RACAH; 10.1016/S0010-4655(00)00234-4 ADFV_v4_0; RACAH; 10.1016/S0010-4655(01)00218-1 ADFV_v5_0; RACAH; 10.1016/S0010-4655(01)00219-3 ADFV_v6_0; RACAH; 10.1016/S0010-4655(02)00591-X ADFV_v7_0; RACAH; 10.1016/S0010-4655(03)00227-3 ADFV_v8_0; RACAH; 10.1016/j.cpc.2004.11.003 ADFV_v9_0; RACAH; 10.1016/j.cpc.2005.12.008 ADFV_v10_0; RACAH; 10.1016/j.cpc.2009.06.018 This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018)