The publications mostly list ν ν Q . e as elementary charge and h as Planck constant are well known or well defined. The nuclear quadrupole moment Q is often determined only very inaccurately (often only with 2-3 digits). Because ν ν Q can be determined much more accurately than Q , it is not useful to specify only V z z because of the error propagation. In addition, ν ν Q is independent of spin! This means that measurements of two different isotopes of the same element can be compared, such as Hg(5/2−), Hg(5/2−) and Hg(9/2−). Further, ν ν Q can be used as finger print method.