Abstract
Hyperfine structure plays a major role in producing "anomalous" odd-to-even isotope ratios in the stepwise excitation, ionization and mass analysis of an element with broad bandwidth, long-pulsed lasers. PAYNE et al. [Spectrochim Acta 46B, 1439 (1992)] proposed that these anomalies may be avoided by cautious application of a simple prescription. We test the prediction by conducting a one-color, two-step ionization experiment on Sn at sufficient laser intensity such that the power-broadened width of a selected resonant transition exceeds the laser bandwidth. The laser is detuned from resonance by an amount greater than the laser bandwidth but less than the power-broadened width. The data obtained in our study confirm the prediction that a slightly detuned resonant ionization scheme effectively eliminates odd/even isotope ionization biases and that operating at adequate laser intensity produces a fairly wide detuning regime over which faithful odd/even isotope ratios are expected. Specifically, detunings of 5-10 cm-1 are sufficient to eliminate these biases in the two-photon stepwise (1 + 1) ionization by way of 3P0 → 3P1 resonance in tin (Sn) at a laser power density of 108 W cm-2.
Original language | English |
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Pages (from-to) | 1057-1066 |
Number of pages | 10 |
Journal | Spectrochimica Acta - Part B Atomic Spectroscopy |
Volume | 49 |
Issue number | 11 |
DOIs | |
State | Published - Sep 1994 |
Scopus Subject Areas
- Analytical Chemistry
- Atomic and Molecular Physics, and Optics
- Instrumentation
- Spectroscopy