Isotopic selectivity calculations for multi-step photoionization of calcium atomsusing narrow-band lasers

Abstract

Isotopic selectivity calculations are carried out for minor calcium isotopes againstthe major isotope 40Ca for the single-resonance two-step and double-resonancethree-step photoionization schemes with narrow-band lasers by using spectralsimulation (SS) and modified spectrum (MS) approaches. The results of thesecalculations are compared with the density matrix (DM) results reported in theliterature. It is noted that the values of isotopic selectivity from the SSapproach do not agree with those from the DM approach whereas theMS approach, considering hole burning in the Doppler-broadened atomicspectrum, predicts selectivity values which are in good agreement withthe DM results. It is argued that one can adequately use the simple MSapproach rather than the complex DM approach for the calculation ofisotopic selectivity of multi-step photoionization with single-frequency lasers.