Hexadecapole interaction in the atomic ground state of165Ho

Abstract

Using the atomic beam magnetic resonance method several hyperfine transitions in the ground state of165Ho were measured at magnetic fields near zero Oe. Including a hexadecapole interaction constantD a perfect fit of the seven hyperfine separations was possible giving the following results:A′=800.583645 (6)MHz,C′=−1.504 (37)kHzB′=−1668.00527 (33)MHz,D′=−0.137 (14)kHz. These interaction constants have been corrected for second order hyperfine interaction within the4I ground multiplet. The corrected constants are the following:A=800.583173 (36)MHz,C=−0.249 (140)kHzB=−1668.078 70 (330) MHz,D=−0.148 (16) kHz. Using a value for 〈r4f/−5〉Ho of Fraga a nuclear hexadecapole moment can be calculated:Π(165Ho)=0.89·10−48cm4. Because of severe uncertainties still present in the theory for calculating the electronic matrix elements this value can be only regarded as highly speculative.