Photodetachment measurements of alkali negative ions

Photodetachment of some atomic negative ions: P?, As?, Sb?, Bi?, Te?, Cr?, Ni?

“…The apparatus used for the experiments has been described in more detail elsewhere [3]. Negative ions are extracted from a Penning ion source, mass selected, and crossed by a wavelength selected light beam.…”

“…In the last few years great progress in photodetachment experiments has been achieved by applying tunable lasers as narrow bandwidth light sources [-1, 2] and by using more advanced ion sources to produce a wider spectrum of ionic species [3,4]. The experiments with tunable lasers have brought new exciting results, as for example, resonances and cusplike structures in the cross sections of alkali negative ions and very exact values of atomic electron affinities.…”

Partial cross sections for Rb? photodetachment in the region of the Rb(5p 2 P 1/2,3/2) thresholds and their analysis by multichannel quantum defect theory

“…ND contains a chemically-cleaned copper surface, inclined by 45 ~ relative to the ion beam direction, from which secondary electrons are released upon impact of the fast neutrals (Rb velocity 4.8.106 cm/s) and accelerated onto the cathode of a 15-stage Cu-Be multiplier (EMI 9603/2 B). The overall detection efficiency of ND was estimated to be 0.25 for the l keV Rb atoms on the basis of the observed signal and the estimated photodetachment probability, assuming a total photodetachment cross section of 5.10-17 cm 2 [15] at 610 nm. Apart from background signals, resulting mainly from electron detachment processes in collisions of Rb-ions with the residual gas (pres-sure about 5.10 _9 Torr=6.6.10 -7 Pa) along an effective pathlength of 30 cm (collisional detachment probability about 5.10-6), the output signal of ND is proportional to the total photodetachment cross section O-tot; note that excited Rb(5p) atoms are detected as Rb(5s) atoms at ND because of their fast radiative decay.…”

Negative ion in a strong optical field

“…Результаты расчетов [61] для иона представлены на рис. 13 кривой Они хорошо согласуются с экспериментальными данными работы [62] (кри вая 2) и теоретическим расчетом методом сильной связи каналов (кри 3) [63]. Аналогичным образом можно учесть корреляционное взаимодей ствие в случае двухфотонных процессов распада отрицательных ионов.…”