The hyperfine structures of the 33715.27 cm−1 and 33706.47 cm−1 transitions from the ground state of singly
ionized Ta have been measured by collinear laser spectroscopy. The structures were found to contain a large
second order contribution. From fitting the observed hyperfine components for both 181Ta and the 180Ta naturally
occurring isomer it was possible to determine the first and second order hyperfine structure coefficients. As
no model independent determination of the nuclear spin of the 180Ta isomer has been performed, fitting was
attempted for a range of spins. A clear chi-squared minimum is obtained for a nuclear spin of 9, in agreement
with model dependent measurements.