U coefficient

U coefficient

[′yü ‚kō·i‚fish·ənt]
(quantum mechanics)
A coefficient that appears in the transformation between modes of coupling eigenfunctions of three angular momenta; it is equal to the product of the Racah coefficient and [(2 j12+ 1) (2 j23+ 1)]½, where j12 and j23 are the intermediate angular momenta in the respective modes.