Two-color photodetachment in the presence of an intense low-frequency radiation field

We report an the photodetachment of a negative ion irradiated by two weak f ields with frequencies omega(1) and, omega(2), in the presence of a stronge r low-frequency radiation field at frequency omega(L). The fields at freque ncies omega(1) and omega(2) are assumed to be so weak that the absorption o f more than one photon of each field is negligible. The low-frequency field is chosen so intense that the exchange of many photons during the photodet achment event is allowed, though, due to its low frequency, the probability of direct photodetachment by multiphoton absorption is negligibly small. B y choosing omega(1) and w2 in such a way that omega(1) - omega(2) = p omega (L), with p an integer number, the results of our calculations may be summa rized as follows. When p is odd, angular distributions of the emitted elect ron, For a fixed value of their energy, result: that show a polar asymmetry that depends on the relative phase between the radiation fields with frequ encies ol and oz, while the energy spectra of the photoelectrons are indepe ndent of phi. On the contrary, when p is even, the energy spectra of the ph otoelectrons are affected by phi, while the angular distributions do not ex hibit ones polar asymmetry.