ClebschGordan
ClebschGordan[{j1, m1}, {j2, m2}, {j, m}] gives the Clebsch–Gordan coefficient for the decomposition of |j, m〉 in terms of |j1, m1〉|j2, m2〉.
Examples
ClebschGordan[{1, 0}, {1, 0}, {0, 0}]
(* -1/Sqrt[3] *)ClebschGordan[{1/2, 1/2}, {1/2, -1/2}, {1, 0}]
(* 1/Sqrt[2] *)Please visit the official Wolfram Language Reference for more details.