DISTORTIONS OF THE ELECTRIC-FIELD GRADIENT OF BR-81 NEAR CRYSTALLINE DEFECT SITES STUDIED BY ENHANCED OPTICALLY DETECTED NQR

During an optical pumping cycle electron spin polarization achieved in the excited triplet state of quinoxaline in p-dibromobenzene was transferred to bromine nuclear spins in the disturbed surrounding shell via induced Δms = 1, ΔmI = 1 transitions and was thus stored in the singlet ground state. Subsequent depolarization by NQR allowed optical detection of 18Br (I = 3 2) in very low concentrations (1000 ppm). © 1979.