We have used the quantum-beat method to study hyperfine structure in the 5'P3/2 and 6'P3/2 states of Z3Na. A pulsed dye laser, frequency-doubled into the uv region, was used to excite sodium atoms abruptly in a beam. The fluorescent light was recorded with a fast transient digitiser, interfaced to a micro-computer. For the magnetic-dipole and the electric-quadrupole interaction constants a and b we obtained: a(52P3,2) = 2.64(1) MHz, b(5'P3/J = 0.38(3) MHz, a(6'P3/2) = 1.39(1) MHz and b(62P3/2)

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... 0.21(2) MHz. Theoretical calculations using many-body perturbation theory were performed for the entire P sequence measured so far, taking polarisation and correlation effects into account separately. Very good agreement between experimental and theoretical values was obtained. the 32P3,2 state by these authors, calculated from 14 different investigations, is about 4% higher than that obtained by Krist et a1 (1977). Taking these considerations into account we give as a recommended value Q(23Na) = 107(5) mb for the quadrupole moment.