Oscillator strengths of selected resonance transitions in neutral sulfur

Abstract

Mean lives and branching ratios for the 4s (3)S<SUP>0</SUP><SUB>1</SUB> and 4s(double prime) (3)P<SUP>0</SUP><SUB>1,2</SUB> levels of neutral sulfur were determined at the Toledo Heavy Ion Accelerator using beam-foil spectroscopic techniques. The mean lives obtained for the 4s (3)S<SUP>0</SUP><SUB>1</SUB> 4s(double prime) (3)P<SUP>0</SUP><SUB>1</SUB>, and (3)P<SUP>0</SUP><SUB>2</SUB> levels, 1.875 +/- 0.094 ns, 2.034 +/- 0.102 ns, and 2.146 +/- 0.129 ns, respectively, represent the most accurate results available to date. Oscillator strengths for the transitions 3p<SUP>4</SUP>(3)P<SUB>2, 1, 0</SUB>-4s (3)S<SUP>0</SUP><SUB>1</SUB> and 3p<SUP>4</SUP>(3)P<SUB>2, 1, 0</SUB>-4s(double prime) (3)P<SUP>0</SUP><SUB>1,2</SUB> were derived from these mean lives together with the measured branching ratios. For comparison with published results which present only multiplet f-values, such f-values were computed from the measured individual line oscillator strengths. The value obtained for the 3p<SUP>4</SUP>(3)P-4s<SUP>3</SUP>S<SUP>0</SUP> multiplet at 1814 A is 0.088 +/- 0.005, in good agreement with the mean of previous experimental measurements and theoretical calculations. With the mean life for the 4s(double prime) 3P<SUP>0</SUP><SUB>0</SUB> level set equal to the mean of our determination for the other two 4s(double prime) (3)P<SUP>0</SUP> levels (a valid assumption for LS coupling conditions, and consistent with the observed equality of the mean lives within the accuracy of our measurement), an oscillator strength for the 1299 A multiplet of 0.121 +/- 0.004 was found. Both results are in good agreement with recent large-scale theoretical calculations that incorporate the effects of configuration interaction.