Hyperfine Structure and Isotope Shift of 30-Year ^207Bi in the 3067-Å Resonance Line*

A 10-m focal length Czerny–Turner monochromator was used to photograph the emission spectrum of 30-year ²⁰⁷Bi in the 3067-Å transition to obtain the hyperfine spectrum and the isotope shift with respect to the naturally occurring isotope ²⁰⁹Bi. A procedure was developed for making a low-impurity electrodeless spectral lamp utilizing only nanogram quantities of ²⁰⁷Bi. The radioisotope was produced in a cyclotron bombardment of natural lead, followed by mass separation. Because the nuclear spin, I, of ²⁰⁷Bi is at present unmeasured, the calculated values for the ²⁰⁷Bi magnetic-dipole and electric-quadrupole constants A and B, respectively, and the isotope shift are based on $I=\frac{9}{2}$, which is expected on the basis of the nuclear-shell model. The results are