THE ZEEMAN-EFFECT IN QUADRUPOLE DOUBLE-RESONANCE SPECTRA - DEPENDENCEOF THE LINE-SHAPES ON THE ORIENTATION OF THE ELECTRIC-FIELD GRADIENT TENSOR

The solid effect spectrum of 1,4-dichlorobenzene was recorded at magne tic field strengths in excess of 50 G; at these field strengths Zeeman structure is seen on the Cl-35 resonance. Unlike in single resonance experiments, peaks are asymmetric, and the high frequency and low freq uency solid effect peaks have not the same shape. Computer calculation of the solid effect spectrum gives peaks which show the same asymmetr y as the experimental spectrum. The simulated line shapes are found to depend on the direction the principal components of the electric fiel d gradient in the crystal framework and indicate that q(yy) lies in th e plane of the benzene ring.