The time differential perturbed angular correlation technique has been used in the measurement of the electric quadrupole interaction of Ta impuritiy in bismuth metal. The interaction frequencies at 293, 400 and 500 K have been observed to be 288±1.5, 266.9±3 and 244.5±4.3 MHz respectively. The electric field gradient at 293 K is 4.75±0.3 × 10¹⁷ V/cm² with the temperature coefficientB=2.2±0.2 × 10⁻⁵ (K)^−3/2.

The hyperfine interaction of¹⁸¹Ta in HfP has been investigated by time differential perturbed angular correlation method which yielded interaction frequencyv_Q=630.20(15) MHz. The observed electric field gradient is calculated to be 1.66(25) × 10²⁰ V/m².