FURTHER COMPUTER-SIMULATION STUDIES OF EXPERIMENTAL ZEEMAN-EFFECT PATTERNS OF MIXED 2ND-ORDER RADIATION OF BI-I

In continuation of a study of so-called forbidden lines (second-order radiation) in general and of the application of computer simulation techniques in particular, two more lines of the Bi I 6p3 ground configuration were investigated. A visual selection of calculated Zeeman profiles best matching the experimental patterns leads to the following estimates of the electric quadrupole admixture: 30% +/- 8% for the 5640-angstrom line and 2.25% +/- 0.5% for the 8755-angstrom line. In the case of the 5640-angstrom line, a better value of the electric quadrupole admixture was obtained, and the limits of uncertainty were reduced by the use of photographic photometry for the conversion of plate density into relative intensities. This was done for the zero-field case. A comparison of the converted experimental hyperfine structure pattern with the calculated profiles gave a final result of 28% +/- 3%. Both investigated lines exhibit a reversed interference phase (reversal of pi-L views) relative to the 7330-angstrom line of PbI. A general and simple rule governing the phase sign is formulated that relates the phase sign to the signs of hyperfine structure splitting constants of the levels involved in the transition. No traces of the 8691-angstrom line were found, even for extended exposures (estimated intensity I8691 < 0.0001I8755). The 3014-angstrom line was observed but not analyzed.