Photodetachment of an electron from a negative ion in the near-threshold region. II. Pulses of radiation with smooth time envelopes

Abstract

For pt.I see ibid., vol.16, p.3641 (1983). The photodetachment of an electron from a negative ion is investigated in the near-threshold region. Pulses of electromagnetic radiation with a smooth envelope are considered. The strong Stark shift of the ground level is shown to influence essentially the regimes of the field-induced decay. The probability of photodetachment is found analytically for the envelope described by the curve f(t)=exp(- mod t mod / tau ). The cases with various relations between the Stark shift, pulse duration tau and detuning from the threshold are analysed. The probability w is found both for a positive and a negative polarisability alpha ( omega ) of the ground state. A partial stabilisation (when alpha ( omega )>0) and destabilisation (when alpha ( omega )<0) of the negative ion due to the strong laser field are discussed.