TENSOR POLARIZABILITIES OF THE (ND+(N+1)S)3(2)D(3 2,5/2) LEVELS IN SC-I, Y-I, LA-I AND LU-I/

A technique based on the detection of nonlinear level-crossing resonan ces in parallel electric and magnetic fields has been extended to the study of the Stark splittings in the hyperfine levels of the ground mu ltiplets (nd+(n+1)s)3 2D3/2,5/2 in Sc I, Y I, La I, and Lu I. Values o f the tensor polarizabilities of the nd electrons were evaluated from the experimental results. The variation of the tensor polarizabilities of the nd electrons in the configurations under study is discussed. T rends of the polarizabilities in different configurations are compared . The ratio between the electric quadrupole constant and the tensor po larizabilities is constant in La and different in Lu, which is caused by a breakdown of the central field model.