Observation of thresholds and overlapping resonances below the 10(2)P(1/2) and P-2(3/2) thresholds in the photodetachment of Cs

• A collinear beam apparatus has been used to study photodetachment of Cs-. Partial cross sections were measured using state-selective detection based on a resonance ionization scheme. Several resonances were observed in the Cs(10(2)S), Cs(6 2F), Cs(6 2G), and Cs(6 2H) final-state channels below the Cs(10(2)P3/2) channel opening. A model was developed to account for the interference between overlapping resonances. This model is essentially a generalization of the Fano [U. Fano, Phys. Rev. 124, 1866 (1961)] and Shore [B. W. Shore, Phys. Rev. 171, 43 (1968)] parametrizations for single resonances. Resonance parameters were extracted by fitting the model to the data sets. The openings of the Cs(10(2)S) and Cs(6 2F) channels, where the polarizabilities of the atomic states are large and positive, showed rapid onsets. In the case of the Cs(6(2)G) and Cs(6(2)H) channels, on the other hand, the photodetachment cross sections increased slowly with energy. For the Cs(6(2)H) channel this is the expected behavior, since it is the result of a large and negative polarizability of the 6(2)H state. In addition, the excitation of the Cs(6(2)H) state with respect to the Cs ground state was found to be 28 356.3(2) cm(-1), in agreement with a previous experiment.

Ämnesord

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

Nyckelord

HIGH-RESOLUTION PHOTODETACHMENT

NEGATIVE-ION PHOTODETACHMENT

DOUBLY-EXCITED STATES

CROSS-SECTION

CESIUM

SPECTRA

RANGE

TRANSITION

APELFELDT H

1992

PHYSICAL REVIEW LETTERS

V69

P2638

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