The E2 admixtures in mixed multipole lines 459.7 nm and 461.5 nm in the spectrum of Bi I

A study of the hyperfine structure of mixed M1 + E2 multipole lines 459.7 nm and 461.5 nm of Bi I are reported. The computer modelling techniques was used to obtain the predicted contour of the hyperfine structure of the lines for different values of the electric-quadrupole admixtures. By variation of free parameters describing the line shape and the electric-quadrupole admixture D, defined as the ratio of the magnetic-dipole and electric-quadrupole decay rates D=A^E2/(A^M1+A^E2), the calculated profiles were fitted into the recorded spectra. The D values of the best fits found are (3.7 ± 0.8)% for the 459.7nm line and (7.7 ± 0.4)% for the 461.5nm. Our result is compared with recent theories and other experiments.